The Encyclopedia Of Nutrition And Good Health - H doc

The odds of heart attack increase with established risk factors: a family history of heartdisease; high blood pressure; obesity; diabetes;increasing age; cigarette smoking; low folic aci

329

haddock (Melanogrammus aeglefinus) A lean

saltwater FISHrelated to COD Haddock is an

impor-tant food fish; its white flesh has a pleasant,

some-what bland taste that can be prepared in any recipe

for cod or FLOUNDER Smoked haddock is called

finnan haddie Haddock is an excellent source of

high-quality PROTEIN; raw, 3.5 oz (100 g) provides

79 calories; protein, 18.3 g; fat, 0.66 g; calcium, 23

mg; cholesterol, 60 mg; niacin, 3 mg; thiamin, 0.04

mg; riboflavin, 0.06 mg

hair analysis A convenient, reasonably

inexpen-sive preliminary screening tool for detecting

min-eral imbalances Because minmin-erals accumulate in

hair as it grows, hair analysis can be used to screen

for accumulated toxic metals, including MERCURY,

ALUMINUM, COPPER, LEAD, and CADMIUM Hair

analy-sis also has been used to assess body levels of trace

minerals (iron, copper, manganese, zinc) and to

compare minerals in populations living in different

regions with differing degrees of pollution and soil

depletion of minerals These hair samples are easily

obtainable, and analytical methods (atomic

absorp-tion spectrometry, X-ray fluorescence

spectrome-try, among others) are sufficiently sensitive to

permit accurate analysis of small samples

However, hair analysis is a controversial test

Some laboratories do not provide reproducible

results, and hair is easily contaminated with

sham-poo, conditioners, dyes, and air pollutants

More-over, findings can be overinterpreted For example,

hair levels of some MINERALS such as SODIUMand

POTASSIUM do not correlate with body levels (See

also HEAVY METALS.)

halibut (Hippoglossus) A flat saltwater FISH

found in all oceans that is one of the most

impor-tant food fishes Resembling a huge FLOUNDER, the

lean flesh is firm with a pleasant flavor and texture.Halibut liver oil is an excellent source of VITAMIN Aand VITAMIN Dand is a primary commercial source

of these vitamins Food value of 3.5 oz (100 g) rawhas: calories, 100; protein, 19.0 g; fat, 1.1 g; cal-cium, 13 mg; cholesterol, 50 mg; niacin, 8.3 mg

ham The rear leg of a hog Ham is a red MEATtaining 34 percent of total CALORIES derived fromsaturated FAT that provides high-quality PROTEINtogether with many VITAMINS and MINERALS Theglistening greenish sheen on the surface of slicedham is a sign of oxidation, not necessarily spoilage

con-To minimize SODIUM intake, patients shouldreduce consumption of all cured pork products,including ham Roasted ham contains per 3 oz (85g): calories, 207; protein, 18.3 g; fat, 14.2 g; choles-terol, 53 mg; iron, 0.74 mg; sodium, 1,009 mg; zinc,1.97 mg; thiamin, 0.51 mg; niacin 3.8 mg; riboflavin,0.21 mg For comparison lean, roasted ham containsper 3 oz.: calories, 133; protein, 21.3 g; fat, 4.7 g; andsodium, 1,128 mg Canned ham contains per 3 oz.:calories, 140; protein, 17.8 g; fat, 7.2 g; sodium, 908

mg (See also DIETARY GUIDELINES FOR AMERICANS; FAT,HIDDEN; FATTY ACIDS.)

hamburger Ground BEEF to which beef fat (beeftallow) can be added to bring the fat content up to

30 percent by weight Hamburger is the most monly eaten MEATin the United States, representing

com-a mcom-ajor contributor of totcom-al fcom-at com-and scom-aturcom-ated fcom-at tothe average diet The average fat in lean ground beef

is 21 percent, while extra-lean hamburger contains

15 percent fat When fat is drained after cooking,both regular hamburger and extra-lean have aboutthe same cooked weight Hamburger can be pre-pared from fresh or frozen beef Fat, water extenders

or binders cannot legally be added Only 12 states

presently require that the fat content of ground beef

be listed on food labels Hamburger and ground beef

need to be cooked thoroughly to destroy possible

disease-producing strains of the bacterium E coli, a

leading cause of food poisoning in the United States

There is no fixed definition of ground beef;

however, if ground beef is designated on the label

as being derived from a particular cut of meat, then

the product must consist of beef derived entirely

from the cut so identified

Ground round roast or top round steak are lower

fat alternatives to hamburger These cuts of meat

contain only 6 percent fat, representing 29 percent

of the total calories Food value of lean hamburger,

per 3 oz (85 g) broiled is: calories, 230; protein, 21

g; fat, 16 g; cholesterol, 74 mg; calcium, 9 mg; iron,

1.8 mg; zinc, 3.74 mg; riboflavin, 0.18 mg; niacin,

4.41 mg; thiamin, 0.04 mg; B6, 0.39 mg For

“regu-lar” hamburger, the value per 3 oz (85 g) broiled is:

calories, 245; protein, 20 g; fat 17.8 g; cholesterol,

76 mg (See also ANTIBIOTICS; CHOLESTEROL.)

hard cider See CIDER

hardening of the arteries See ARTERIOSCLEROSIS

hard water See WATER

hawthorn (Crataegus oxyacantha) A spiny tree

or hedge native to Europe whose berries have

medicinal properties Folk traditions describe the

use of berries and flowers as beneficial

supple-ments for INFLAMMATIONranging from ARTHRITISto

sore throats; for vascular conditions such as angina,

high blood pressure, and clogged arteries

Sub-stances in hawthorn extracts inhibit constriction of

blood vessels and strengthen arterial walls,

poten-tially protecting against plaque deposits

Hawthorn berries and blossoms contain FLA

-VONOIDS, particularly anthocyanins and

proantho-cyanins, colored pigments of berries including

blueberries, cherries, and grapes These flavonoid

compounds stabilize collagen, the primary

struc-tural protein of connective tissue, as well as of

tendons, cartilage, and ligaments They act as

antioxidants, prevent FREE RADICAL damage, and

prevent the release and synthesis of substances that

promote inflammation, such as prostaglandins, tamines, and leukotrienes Hawthorn is unsafe forpregnant women; data for breast-feeding womenare inadequate

his-Hazard Analysis and Critical Control Points

(HACCP) A food safety program initially adopted

by the U.S FDAin 2001 for seafood and juice; tually, the agency plans to expand it to the entireU.S food supply Based on a similar program devel-oped for astronauts in the 1970s, HACCP focuses

even-on preventing hazards that could cause food-borneillnesses by applying science-based controls, fromraw material to finished product

The FDA describes the seven principles ofHACCP as follows:

• Analyze hazards. Potential hazards ated with a food and measures to control thosehazards are identified The hazard could be bio-logical, such as a microbe; chemical, such as atoxin; or physical, such as ground glass or metalfragments

associ-• Identify critical control points. These arepoints in a food’s production, from its raw statethrough processing and shipping to consumption

by the consumer, at which the potential hazardcan be controlled or eliminated Examples arecooking, cooling, packaging, and metal detection

• Establish preventive measures with critical

limits for each control point. For a cookedfood, for example, this might include setting theminimum cooking temperature and timerequired to ensure the elimination of any harm-ful microbes

• Establish procedures to monitor the critical

control points. Such procedures mightinclude determining how and by whom cookingtime and temperature should be monitored

• Establish corrective actions to be taken

when monitoring shows that a critical limit has not been met. This might entail,for example, reprocessing or disposing of food ifthe minimum cooking temperature were notmet

• Establish procedures to verify that the

sys-tem is working properly. This mightinvolve, for example, testing time-and-tempera-

330 hard cider

ture recording devices to verify that a cooking

unit is working properly

• Establish effective record-keeping to

docu-ment the HACCP system. This would

include records of hazards and their control

methods, the monitoring of safety requirements,

and action taken to correct potential problems

Each of these principles must be backed by

sound scientific knowledge: for example,

pub-lished microbiological studies on time and

tem-perature factors for controlling food-borne

pathogens

This new food safety program was adopted by

the FDA as a way to meet the challenges of

increas-ing numbers of food pathogens, includincreas-ing

ESCHERICHIA COLI0157:H7 and SALMONELLA

hazelnut (filbert, cobnut) A sweet, grape-sized nut

of a deciduous shrub or small tree that is related to

the birch The hazelnut is one of the world’s largest

nut crops; it is commercially grown in the United

States, Spain, Turkey, and Italy A native of Europe

and Asia Minor, it grows well in regions with mild,

moist winters and cool summers “Divining rods”

made from the wood of the tree were believed to

have the power to seek out treasure or pockets of

valuable minerals Chopped or ground hazelnuts

are often used as flavorings in desserts and sweet

snacks The brown whole nuts are often included

in holiday mixes at Christmas A quarter cup

serv-ing provides: calories, 180; fat 16 g; fiber, 4 g;

pro-tein, 5 g

HCl See STOMACH ACID

HDL See HIGH-DENSITY LIPOPROTEIN

head cheese A cold cut prepared from the MEAT

of a calf and pig heads, (including cheeks, snouts,

lips) together with brains, hearts, tongues, and feet

The cooked meat, stripped from bones, is ground,

seasoned, and then pressed to create a single jellied

mass (See also BEEF; FOOD PROCESSING; HAM.)

heart attack A condition (also known as

myocar-dial infarction) resulting from a blocked coronary

artery, an artery feeding the heart When oxygensupplied to the heart muscle is compromised, thetissue may be irreparably damaged

Symptoms include prolonged pressure orpainful tightness at the center of the chest, possiblyspreading to the left arm and shoulder and to theneck and jaw There may also be nausea and vom-iting, shortness of breath, and sweating

The odds of heart attack increase with established risk factors: a family history of heartdisease; high blood pressure; obesity; diabetes;increasing age; cigarette smoking; low folic acid; ahigh intake of saturated fat; a sedentary lifestyle;and repressed anger/anxiety A healthful diet, reg-ular exercise, stress management, social and emo-tional support, maintaining a desirable bodyweight, avoiding smoking, and a semi-vegetariandiet with reduced fat are recommended

well-Blood clots are one of the dangers of cloggedarteries When clots lodge in arteries feeding theheart, they block blood flow The heart requires aconstant supply of nutrients and oxygen from theblood, and being deprived of oxygen even brieflywill damage the heart muscle

It is critically important to secure immediatemedical care for a heart attack by dialing 911 Manyheart attack patients die before they get to the hos-pital, and delays in summoning help can be fatal.(See also ATHEROSCLEROSIS; BLOOD CLOTTING; CHOLES-TEROL; CORONARY ARTERY DISEASE; HOMOCYSTEINE;STROKE.)

Morrison H I et al “Serum Folate and Risk of Fatal

Coronary Heart Disease,” Journal of the American

Med-ical Association 275, no 24 (June 26, 1996):

1,893–1,896.

U.S Department of Health, Education and Welfare, How

Doctors Diagnose Heart Disease Washington, D.C.:

DHEW Publication No (NIH) 78–753.

heartburn See ACID INDIGESTION

heart disease See ATHEROSCLEROSIS; CARDIOVAS CULAR DISEASE; CORONARY ARTERY DISEASE; HEART ATTACK; STROKE

-heart-healthy diet See CHOLESTEROL; DIETARY GUIDELINES FOR AMERICANS

heart-healthy diet 331

332 heat inactivation

heat inactivation The loss of biological activity of

a substance, such as an ENZYME, when heated to

suf-ficiently high temperatures In the case of enzymes,

heat alters structures critical for catalysts COOKING

at high temperatures destroys vitamins such as VIT

-AMIN C, FOLIC ACID, and THIAMIN Through oxidation

or other chemical changes, polyunsaturated FATTY

ACIDSand even CHOLESTEROLbecome oxidized when

heated at sufficiently high temperature in the

presence of air The essential AMINO ACID, LYSINE, is

partially destroyed when grain protein and

carbo-hydrate are heated together Several processed

BREAKFAST CEREALScontain less lysine than that

pre-sent in flour because they have been baked

heavy metals Industrial chemicals of LEAD, MER

-CURY, CADMIUM, CHROMIUM, NICKEL, antimony, and

ARSENIC These chemicals are general enzyme

poi-sons, and the toxic effects of these industrial wastes

is well established As an example, lead exposure

causes ANEMIA by blocking a key step in the

syn-thesis of HEMOGLOBIN, required for the formation of

RED BLOOD CELLS

As a general rule, the greater the exposure to a

toxic metal, the greater the risk of poisoning

Wide-spread pollution has created chronic low-level

exposure in many regions of the United States,

thus increasing the risk of heavy metal poisoning

Therefore, minimizing heavy metal exposure in air,

food, and WATER can lead to dramatic, long-term

health benefits

Nutrients like sulfur-containing amino acids,

selenium, and VITAMIN Cseem to have the ability to

counteract heavy metals in the body, while diets

low in CALCIUM, IRON, or ZINCincrease lead uptake

The body has several defense mechanisms against

toxic exposure One of these is metallothionens,

proteins rich in the sulfur amino acid CYSTEINEthat

bind heavy metals and speed their removal

Metal-lothionen synthesis is triggered by exposure to

heavy metal ions The following are specific

exam-ples of common toxic metals:

Arsenic, which occurs in PESTICIDES, smog and

cigarette smoke, is believed to interfere with

neu-rological development, and high doses increase the

risk of some types of cancer Cadmium may cause

high blood pressure and heart abnormalities,

bron-chitis, lung fibrosis, and emphysema Small

amounts are common in consumer items rangingfrom cigarettes and pesticides to food Drinkingwater may be contaminated with cadmiumbecause soft water dissolves the cadmium in galva-nized pipes

Lead exposure leads to distractibility, DIARRHEA,irritability, and lethargy More serious conse-quences are smaller fetal brain size, increased BIRTH DEFECTS, decreased IQ, anemia, CHRONIC FATIGUE,aching limbs, kidney disease, and sometimes coma.Though the U.S EPAbanned leaded paints and hasrequired lowered lead levels in gasoline, Americansstill are exposed to lead through drinking water,glazed ceramic dinnerware, old paint, and decades

of environmental pollution

Selenium is a water and soil contaminant insome regions of the United States In traceamounts, the appropriate chemical form of sele-nium is an essential nutrient However, the margin

of safety of selenium is small, and ingesting onlyfive times the level deemed safe and adequate cancause toxic side effects (See also BREAST-FEEDING.)

height/weight tables Standards of weight andheight by age used to assess an appropriate bodyweight for normal people Several different tableshave been developed The Metropolitan Life Insur-ance Company assembled the best-knownheight/weight table, based upon the heights andweights of policy holders It was later realized thatweight depends on body build; therefore, valuesfor an “IDEAL BODY WEIGHT” were adjusted byincluding different values for “small,” “medium,”and “large” body sizes Since ideal body weightimplies making a judgment and is subjective, amore liberal version of these tables was published

in 1983, based on data obtained from 1959 to

1983 The 1983 revision came up with a “desirablebody weight” that is 10 percent greater than that

on the older table This revision suggests that awoman of average frame and average height (5 feet

4 inches) wearing 3 pounds of clothing and ing one-inch heels would weigh 126 to 138pounds For an average man (5 feet 9 inches tall,wearing five pounds of clothing), the range is 148

wear-to 160 pounds

Several limitations of life insurance tables restricttheir usefulness Their weights are based on values

that were simply reported, not measured Insurance

policy holders for whom the data were collected do

not represent the whole U.S population High

blood pressure, smoking, and diabetes—factors that

can affect general health and body weight—are not

considered There is no firm definition of “frame

size.” Thus, tables of this kind represent a subjective

evaluation The tables would suggest that a wide

range of weights (30 to 40 pounds) poses no risk, in

contradiction to common experience Newer

infor-mation indicates that excess FAT, not weight, is

crit-ical Furthermore, it is important to establish how

the fat is distributed in order to assess risks (See

also BODY MASS INDEX; OBESITY.)

Helicobacter pylori (Campylobacter pylori) A

spiral-shaped bacterium that can infect the

stom-ach and cause GASTRIC ULCERS, duodenal ulcers and

symptomatic, atrophic GASTRITIS (stomach

inflam-mation), and a higher risk for stomach cancer

Almost 90 percent of patients with the most

com-mon type of stomach CANCER, intestinal-type

gas-tric adenocarcinoma, are infected with H pylori.

While stomach acid kills many bacteria, H pylori

burrows deep into the mucus layer to the

underly-ing mucosal cell surface, where it is protected from

stomach acid Half of all Americans over the age of

50, and 75 percent of subjects older than 65 have

antibodies against H pylori, suggesting a wide

prevalence of infection While many adults exhibit

evidence of antibodies to this bacterium, it is not

clear why only a small percentage develop

duode-nal ulcers On the other hand, irradiation of H.

pylori with bismuth compounds combined with

several antibiotics decreases the risk of ulcer

relapse and yields a significant improvement in

ulcers and stomach inflammation Researchers

have discovered that BROCCOLIand broccoli sprouts

contain a chemical, SULFORAFANE, that kills H pylori

in mice Similar studies on humans are ongoing

(See also GASTROINTESTINAL DISORDERS.)

hematocrit A clinical lab test used to assess the

health of red blood cells The hematocrit represents

the volume of packed red blood cells, expressed as

the percentage of total blood volume For men, the

average hematocrit is 47 percent with a range of 40

percent to 54 percent and for women, the average

is 42 percent with a range of 37 percent to 47 cent Children’s hematocrit varies depending onthe age Serious fluid loss without cell loss, as inDEHYDRATION, raises the hematocrit, while bloodloss or ANEMIA lowers the hematocrit (See alsoHEMOGLOBIN.)

per-heme An IRON-containing red pigment found inred blood cells HEMOGLOBIN, the oxygen transportprotein of blood, requires heme to bind molecularoxygen reversibly Heme also functions as a helpergroup of CYTOCHROMES, enzymes responsible fortransporting electrons in energy-generating reac-tions of MITOCHONDRIA

Heme is synthesized in the bone marrow by theparents of red blood cells (reticulo-endothelialcells) Iron is bound within a complex ring struc-ture, synthesized from small building blocks:GLYCINE, the simplest AMINO ACID, and SUCCINIC ACID, produced from fat and carbohydrate break-down Heme synthesis requires VITAMIN B6, andLEAD inhibits the process Therefore vitamin B6deficiency and lead poisoning cause ANEMIA Whenthe spleen removes wornout red blood cells it con-verts heme to the BILE PIGMENT, bilirubin, and recy-cles the released iron

Much of the iron in meat, fish, and poultryoccurs as heme, which is readily absorbed by theintestine Absorption of this heme iron is notdiminished by PHYTIC ACID, a metal binder occur-ring in certain plant materials, nor is it increased byVITAMIN C In contrast, most of the iron in vegeta-bles is not bound to heme and is less readilyabsorbed The efficiency of nonheme iron absorp-tion from plant sources is only 10 percent to 20percent that of heme iron Vitamin C increases theuptake of iron from nonheme sources Some forms

of FIBERbind minerals and lower intestinal tion of nonheme iron

absorp-hemicellulose A form of dietary FIBER, plant rial resistant to digestive enzymes Hemicellulosehelps form plant cell walls Annual plants contain 15percent to 30 percent hemicellulose by dry weight intheir cell walls, while wood contains 20 percent to

mate-25 percent hemicellulose Dietary sources of cellulose include FRUIT, vegetables, LEGUMES, cereal,BRAN, whole-grain flours, nuts, and seeds Dietary

hemi-hemicellulose 333

hemicelluloses absorb water, provide bulk, and

soften stools They are broken down by intestinal

bacteria Excessive amounts of hemicelluloses may

interfere with mineral absorption

Hemicellulose is structurally distinct from

water-soluble fibers such as gums and pectin and

insolu-ble fiber like CELLULOSE Hemicellulose contains

long chains of repeating sugar units Pentosans are

chains of PENTOSES, five-carbon sugars like xylose

and arabinose Pentosans form the largest group

and occur in CEREAL GRAINS Galactosans, chains of

the simple sugar GALACTOSE, form a second group

Acidic hemicelluloses also occur in food

hemochromatosis A rare condition caused by

excessive IRON deposits in tissues, including the

LIVER, PANCREAS, and skin Symptoms include liver

enlargement, weakness, moderate weight loss,

bronzed skin, diabetes, and, eventually, heart

fail-ure Hemochromatosis is 10 times more frequent in

men than in women

Abnormal iron metabolism can be caused by a

genetic defect (primary hemochromatosis)

charac-terized by increased accumulation of iron in tissues

The inherited trait for iron storage disease is

rela-tively common among whites, affecting perhaps as

many as one person in two hundred This suggests

that the tendency to accumulate dietary iron is a

more general problem in the U.S than generally

rec-ognized Alternatively, excessive iron consumption

can lead to abnormally high iron storage (secondary

hemochromatosis) This can occur with chronic iron

supplementation in men, because they do not

usu-ally lose iron, and in alcoholics, because several

alco-holic beverages contain iron (See also FERRITIN.)

hemoglobin The oxygen transport protein of

blood and the predominant protein in red blood

cells Hemoglobin is a complex PROTEIN; it contains

a total of four individual amino acid chains called

globins Adult hemoglobin contains two alpha

glo-bin chains and two beta gloglo-bin chains Hemogloglo-bin

also contains the iron-containing pigment HEME,

which is required to bind oxygen Heme imparts a

red color to hemoglobin and to red blood cells

Hemoglobin is a dynamic molecule and changes

its shape and oxygen-carrying characteristics to help

regulate oxygen delivery and blood pH It binds

oxy-gen when the oxyoxy-gen concentration is high in blood

exposed to air in the lungs Next, arteries carry oxygen-rich red blood cells from the lungs to capil-laries, where hemoglobin responds by releasingmore of its bound oxygen (the Bohr effect) The re-leased oxygen then diffuses into cells to enable them

to continue the oxidation of fuel molecules Duringthis process of shedding oxygen molecules hemoglo-bin binds carbon dioxide and hydrogen ions andreturns them to the lungs via the veins In the lungshemoglobin picks up more oxygen and simultane-ously releases carbon dioxide and hydrogen ions

An adult normally produces 6.25 g of bin daily The hemoglobin blood content of women

hemoglo-is 12 to 16 g per 100 ml of blood, and of men, 14 to

18 g ANEMIA is a deficiency of normal red bloodcells Deficiencies of IRON, VITAMIN A, VITAMIN B6,VITAMIN B12, VITAMIN D, VITAMIN E, and FOLIC ACIDmay cause anemia

Over 400 mutant hemoglobins are known Most

do not alter normal physiological function ofhemoglobin However, certain mutations lead toabnormal hemoglobins that malfunction and pro-duce fragile red blood cells and, consequently, ane-mia, including sickle cell anemia and thalassemias.Alteration of a single amino acid in a chain of 146amino acids causes sickle cell anemia

Environmental factors can decrease hemoglobinfunction Carbon monoxide poisons hemoglobin,and cigarette smokers’ blood contains much morecarbon monoxide than that of nonsmokers Fur-thermore, babies born to smoking women aresmaller than average because they receive less oxy-gen during fetal development (See also ERYTHRO-POIESIS; HEMATOCRIT.)

Davie, Sarah J et al “Effect of Vitamin C on

Glycosyla-tion of Proteins,” Diabetes 41 (1992): 167–173.

hemolytic anemia A deficiency of red blood cellscaused by their rapid destruction and characterized

by chronic fatigue Typically, hemoglobin down products accumulate, leading to JAUNDICE,the accumulation of yellow pigment in the skinand in the whites of the eyes Rapid turnover of redblood cells may be caused by genetic diseases thatlead to the production of abnormal HEMOGLOBIN, as

break-in sickle cell ANEMIA and thalassemias Defects inred blood cell enzymes can also cause hemolyticanemia A deficiency of one such enzyme, glucose-

334 hemochromatosis

herbal medicine 335

6-phosphate dehydrogenase that helps maintain

adequate levels of GLUTATHIONE, a cellular ANTIOXI

-DANT, is the most common of these defects

Acquired hemolytic anemia can be caused by

expo-sure to potentially damaging chemicals, including

certain drugs (antimalarials, pimaquine, and

Atra-bine) (See also IRON.)

hemolytic-uremic syndrome See ESCHERICHIA COLI

hemosiderosis A condition associated with

excessive iron deposition, particularly in the LIVER

and spleen Hemosiderin is the insoluble iron

com-plex formed in the liver with iron accumulation

Hemosiderosis can be caused by:

1 excessive red blood breakdown associated with

chronic infection, malaria, hemolytic anemias,

PERNICIOUS ANEMIA, or multiple blood

transfu-sions;

2 excessive uptake of dietary iron;

3 impaired utilization of iron

Under severe conditions, with extreme

accumu-lation of iron, the resulting disease is called

HEMOCHROMATOSIS This condition in turn causes

liver damage and pancreatic damage, which can

lead to DIABETES

heparin A carbohydrate that is a naturally

occur-ring anticoagulant (prevents blood from clotting)

Heparin is produced by mast cells (cells that also

contain inflammatory agents like histamine) in

connective tissue, the liver and certain white blood

cells Heparin prevents the formation of FIBRIN

clots (Fibrin is the insoluble protein produced

when blood clotting is triggered.) In capillaries,

heparin also activates the lipoprotein LIPASE, the

enzyme that releases FATTY ACIDS from CHYLOMI

-CRONSand VERY LOW-DENSITY LIPOPROTEINS, particles

that transport fat in the blood (See also FAT METAB

-OLISM; GLYCOSAMINOGLYCANS.)

hepatic Refers to the LIVER

hepatitis Chronic inflammation of the LIVER

Symptoms include JAUNDICE, liver enlargement,

fever, and gastrointestinal disturbances Hepatitis

can cause a loss of APPETITE, headache, and achange in taste sensation It can interfere withDIGESTION, leading to MALNUTRITION Hepatitis can

be caused by drugs, poisons, and viruses

Infectious hepatitis refers to a family of viral eases spread orally Hepatitis A is caused by thehepatitis A virus usually transmitted orally throughfecal contamination of food utensils, due to poorhygiene by food workers who have been infectedwith the virus Fecal contamination can also spreadthrough drinking WATER Eating shellfish contami-nated by raw sewage is a common cause of infec-tious hepatitis The long incubation period, three tosix weeks, makes it difficult to associate hepatitiswith a specific food GAMMA GLOBULINmay preventthe disease, provided the shots are administeredsoon after exposure Travelers to countries typified

dis-by poor sanitation may be advised to receivegamma globulin shots, which will offer protectionfor up to three or four months Hepatitis E is anenteric (small intestinal) form of hepatitis that hasbeen associated with waterborne outbreaks ofhepatitis in developing countries Other forms ofhepatitis (such as hepatitis B and hepatitis C) arespread through blood (See also FOOD POISONING.)

Fried, M W “Therapy of Chronic Viral Hepatitis,” Medical

Clinics of North America 80, no 5 (September 1996):

957–972.

herbal medicine (botanical medicine) The branch

of medicine that emphasizes the therapeutic erties of plants Ancient medical traditions fromIndia (ayurvedic medicine) and China (orientalmedicine) and others emphasize the health bene-fits of specific plants and plant products, and med-icinal plants provided the foundation of themodern pharmaceutical industry Recent environ-mental awareness of the diversity of species inthreatened tropical rain forests has rekindledresearch in the pharmacological effects of indige-nous plants Although natural products, they offerthe advantage of containing multiple active princi-ples that possess a variety of often complementaryproperties Often, the active ingredients of herbscorrect an underlying problem rather than simplytreating a symptom Most herbal preparations areconsidered foods by the U.S FDAand they cannot

prop-be laprop-beled with health claims

Quality control is an issue with herbal

prepara-tions Their potency is affected by the plant’s age at

the time of harvest, the season of harvest, the type

of soil used for cultivation, the climate, and the

methods of storage and preparation Producers

often measure the amounts of active ingredients in

a given herbal preparation or extract and then

adjust the strength to a standard level to assure a

reproducible activity

The appropriate amount consumed is a second

concern; an amount that is safe for an adult may

not be safe for a child Some herbs are appropriate

for short-term use, and not for long periods

A third concern is safety According to the U.S

FDA, extracts of the following plants are potentially

dangerous: arnica, belladonna (deadly nightshade),

Culcana, blood root, Scotch broom, buckeye nuts,

heliotrope, hemlock, henbane, jalop root,

jimson-weed, lily of the valley, lobelia, mandrake,

mistle-toe, morning glory, periwinkle, St.-John’s-wort,

spindle bean, tonka bean, snakeroot, and

worm-wood (once used to flavor absinthe, a liqueur)

Often foods themselves provide substances that

promote health Beyond the nutrients they

con-tain, ONIONS, GARLIC, CHILI PEPPERS, LICORICE, TUR

-MERIC, CRANBERRY, GINGER, DANDELION, BLUEBERRIES,

and cherries contain a variety of substances that

fight infection, reduce the risk of cancer, stimulate

the nervous system or reduce inflammation (See

also ALFALFA; CHAMOMILE; COMFREY; GINSENG; GOLD

-ENSEAL; HAWTHORN; PEPPERMINT; SARSAPARILLA;

STRAWBERRY.)

Wehrbach, M R., and M T Murray Botanical Influences on

Illness Tarzana, Calif.: Third Line Press, 1994.

herbicides A diverse family of chemicals used to

kill weeds during cultivation of crops Many

herbi-cides are suspected of causing CANCER or BIRTH

DEFECTS The health risks of herbicides are greatest

for those with chronic exposure, such as farm

workers and professional applicators The following

herbicides are examples currently in use:

• Alachlor is a widely used herbicide and is among

the most dangerous

• Atrazine accounts for about 10 percent of PESTI

-CIDEsales in the United States and was restricted

by 1991 This herbicide has been found to

widely contaminate underground water plies in the United States

sup-• Dinoseb was subject to an emergency ban by theEPA in 1986 because of a possible link to birthdefects, skin rashes, cancer, and sterility inexperimental animals Because a substitute wasnot developed, the EPA permitted the continueduse of Dinoseb on LENTILS, PEAS, CHICKPEAS,green beans, and RASPBERRIES

• Linuron is a common herbicide used on SOY BEANS, carrots, celery, asparagus, corn, potatoes,and wheat It is associated with tumors in exper-imental animals Linuron frequently contami-nates water supplies,

-• Paraquat is used to treat fields before planting orbefore harvest It is used extensively in soybeanagriculture and in orchards Paraquat cannot bewashed off produce, and direct exposure to thischemical is hazardous Inhalation of its mistcauses lung inflammation and repeated expo-sure can lead to kidney and lung damage It isalso toxic to fish

• 2,4-D is widely used by home owners and homegardeners to kill dandelions It is the toxic agent

in over 1,500 pesticide products Exposure isgreatest for children and animals who play intreated areas Farmers use 2,4-D on CORN,WHEATS, and hay A National Cancer Institutestudy linked this weed killer with cancer of lym-phoid tissue in experimental animals (See alsoDIOXIN; PESTICIDES.)

herbs The leaves, shoots, stems, and seeds ofmany widely distributed plants In contrast, SPICESare prepared from the FRUIT, bark, or pepper cornsfrom tropical plants Culinary herbs have appealingaromatic or savory characteristics and make foodtasty and flavorful In addition many herbs affectphysiological processes, which is the basis for theirmedicinal properties In some cases, research hasprovided deeper insights into the active ingredients.Culinary herbs that exhibit physiologic effectsinclude:

• ANISEand CARAWAYmay relieve gas and stomachcramps Caraway contains carvacrol, a com-pound that eases muscle spasms

• Carrot seed may relax smooth muscles, relievestomach cramps, and lower blood pressure

336 herbicides

• Celery seed contains phthalides, chemicals that

are sedatives Celery seed has antibiotic activity

Celery juice may lower blood pressure

• CHERVILcontains the mild carcinogen estragole,

which is also found in basil and tarragon

• Coriander (cilantro) may lower BLOOD SUGAR

and increase GLUCOSE TOLERANCE Coriander

lowers blood fat According to folklore, it curbs

bad breath

• Dill oil reduces cramps, lowers blood pressure,

and slows heartbeat in experimental animals

Dill water reduces colic, according to folklore

• FENNEL contains sulfur compounds that relieve

cramps According to folklore, it helps with colic

and upset stomach

• LOVAGE seeds, leaf, and root can be steeped in

boiling water to prepare a tea, used in folk

med-icine to reduce water retention and ease joint

pain Lovage increases urination and water loss

in experimental animals

• PARSLEY lowers blood pressure and stimulates

uterine contractions in experimental animals

Parsley acts as a mild LAXATIVEand also freshens

the breath Parsley oil contains apiol and

myris-ticin, which induce menstruation Parsley oil

can induce miscarriages and should not be

administered during pregnancy

Herbs of the mint family that exhibit physiologic

effects:

• BASIL relieves FLATULENCE and gastrointestinal

discomfort

• Lemon balm is an ANTIOXIDANT Animal studies

suggest the oil relieves inflammation

• MARJORAM may relax smooth muscles and

re-lieve stomach cramps According to folklore,

marjoram tea eases cramps and upset stomach

• OREGANOcan function as an antiseptic Its oil

con-tains carvacrol, which possesses broad

anti-microbial properties It relieves upset stomach and

is a smooth muscle relaxant According to

folk-lore, chewing oregano reduces toothache pain

• ROSEMARYand SAGEcontain strong antioxidants

Like CLOVES, oregano, and GINGER, they have

long been used to preserve food Sage is used

commercially to preserve salad oil and potato

chips According to folklore, rosemary aids

memory and induces sleep

• THYMEcontains thymol, an antiseptic Thyme isused as a mouth wash Oil of thyme causes dan-gerous side effects, however

hermetically sealed Refers to food containersthat do not permit entry of either microorganisms

or air For example, bottled or canned foods arehermetically sealed (See also FOOD PROCESSING.)

herring (Clupea harengus) A small, saltwaterFISH related to the shad and SARDINE Silvery andstreamlined, the herring reaches a length of 10 in

at maturity A freshwater variety is known as cisco.Herring is an important food fish that is alsoprocessed for animal feed Intensive fishing prac-tices worldwide have placed this fish in jeopardy.Herring is an oily fish, and most of the fat isunsaturated It is available frozen, pickled, orsmoked Herring roe is used to prepare CAVIAR.Pickled herring, 3 oz (85 g), provides calories, 190;protein, 17.3 g; fat, 12.8 g; cholesterol, 66 mg; cal-cium, 31 mg; iron, 1.2 mg; sodium, 1.38 mg; zinc,0.85 mg; vitamin A equivalents, 20; niacin, 2 mg;thiamin, 0.04 mg; riboflavin, 0.18 mg

hesperidin A substance found in rinds of ORANGESand lemons and in the peels of ripe fruit A matureorange contains about a gram of hesperidin CitrusFLAVONOIDS are commercially extracted from thepulp remaining after juicing oranges and lemons.Hesperidin is believed to strengthen capillary walls

in conjunction with VITAMIN C Like most noids, it is also an ANTIOXIDANTand limits oxidativedamage (See also CITRUS FRUIT.)

flavo-heterocrine Refers to tissues that secrete ent types of materials The PANCREAS is a notableexample; it combines an endocrine function (secre-tion of hormones INSULIN and GLUCAGON directlyinto the blood) and an exocrine function (secretion

differ-of digestive enzymes into the intestine) (See alsoENDOCRINE SYSTEM.)

heterocyclic amines (HCAs) A family of causing agents that occur in cooked MEAT HCAstend to form inside meat with longer cooking timesand higher temperatures of barbecuing They can-

cancer-heterocyclic amines 337

338 hexose

not be scraped off and once eaten they can become

activated to attack DNA of cells, a possible first step

in cancer development HCAs can also inflame the

heart

There are several ways to minimize the risk of

HCAs Precooking hamburger for a short time

before barbecuing seems to eliminate some of the

compounds that can form HCAs On the other

hand, green and black tea contain tannins, bitter

substances in brewed tea, that can block the ability

of HCAs to damage DNA Garlic and onions behave

similarly The green plant pigment chlorophyll can

also block the damaging effects of HCAs

Supple-menting with the bifidobacteria can protect the

COLONagainst HCAs (See also CARCINOGEN.)

hexose A large class of simple sugars composed of

six carbon atoms that can serve as an energy source

FRUCTOSEand GLUCOSE are the two most important

hexoses in the diet As BLOOD SUGAR, glucose is the

most important CARBOHYDRATEfuel in the body

Hex-oses also function as building blocks for more

com-plex sugars and for important large molecular weight

carbohydrates Thus, fructose is linked to glucose in

table sugar, and LACTOSE contains two hexoses,

GALACTOSE and glucose Polymerized MANNOSE is

found in glucomannan, a form of fiber STARCH,

GLYCOGEN, and CELLULOSEare polysaccharides made

from glucose (See also NATURAL SWEETENERS.)

hiatus hernia (hiatal hernia) The protrusion or

bulging of the STOMACH through the esophageal

opening (hiatus) of the diaphragm into the chest

Aging or damage of supportive tissue can lead to

hiatus hernia and DIVERTICULOSIS, which is the

bulging of the large intestine For Americans,

there is a 50 percent chance of having a hiatus

hernia after the age of 40 Symptoms resemble

DYSPEPSIA, including a burning pain under the

breastbone and heartburn in which stomach

con-tents regurgitate into the ESOPHAGUS, causing

inflammation Inability to breathe deeply and

fre-quent belching are also experienced Symptoms

are most noticeable after a large meal, when

straining or when stooping

Hiatus hernia is often a recurrent condition

Several steps can be taken to minimize its effects

• Eat in a peaceful environment

• Receive physical manipulation by a skilled apist or bouncing on one’s heels to move thestomach down into place

ther-• Avoid swallowing air; this inflates the stomach

• Take licorice extract

hidden fat See FAT

high blood pressure See HYPERTENSION

high-calorie foods See FAT, HIDDEN

high complex carbohydrate diet See DIET, HIGH COMPLEX CARBOHYDRATE

high-density lipoprotein (HDL) A type of protein complex or particle in the blood that scav-enges CHOLESTEROL from peripheral tissues andtransports it to the LIVER for disposal HDL’s func-tion is opposite that of LOW-DENSITY LIPOPROTEIN(LDL), which transports cholesterol to tissues HDLcan transfer cholesterol to another lipid carrier,VERY LOW-DENSITY LIPOPROTEIN(VLDL), prior to itsconversion to LDL

lipid-Because HDL possesses the highest protein tent, which is more dense than lipid, HDL is thedensest of the various circulating lipoproteins HDLprecursor is synthesized by the liver HDL3 is anintermediate form, to which lipids and proteins areadded from other lipoproteins in the circulation.The mature, spherical HDL is called HDL2 Gener-ally speaking, the higher the HDL level, the lowerthe risk of ATHEROSCLEROSIS Women have a lowerrisk of heart disease than men and their HDL levelsare higher Evidence suggests that HDL3 isinversely linked to the risk of coronary heart dis-ease more strongly than HDL2

con-HDL contains proteins that determine its role.For example, Apoprotein D catalyzes cholesteroltransfer between HDL and LDL, and ApoproteinCII is transferred to VLDL and CHYLOMICRONS,enabling these lipoproteins to interact in capillaries

histamine 339

to release fatty acids from the fat they carry so that

fatty acids can be taken up by cells HDL salvages

Apoprotein CII from chylomicron and VLDL

rem-nants for recycling Apoprotein AI activates an

enzyme that converts cholesterol to a storage form

Strategies to Raise HDL Levels

Though HDL is not a nutrient and cannot be

con-sumed, a variety of approaches can raise or at least

maintain HDL levels while lowering LDL

choles-terol:

• Exercising: Even moderate, regular physical

exercise appears to increase HDL levels

• Losing weight: Obesity is correlated with

decreased HDL levels

• Avoiding cigarettes: Smoking decreases HDL

levels

• Eating less FATand oils, especially less saturated

fat The more saturated fats in the diet, the

higher the level of LDL, the less desirable form

of cholesterol Substituting OLIVE OILand other

monounsaturates in place of other cooking oils

may be beneficial by raising HDL levels

• Eating FISHin place of red meat several times a

week Fish and fish oil may help raise HDL while

lowering LDL levels

• Eating more whole grains, vegetables, and

legumes

HDL Measurements

Guidelines suggest that if the serum cholesterol

level is about 200, it is worthwhile to have a

lipoprotein analysis, which measures HDL, LDL,

and blood fat levels Usually HDL levels are

expressed as a ratio of total cholesterol/HDL A

ratio of 4.0 correlates with an average risk of heart

disease, and a ratio above 4.0 suggests the risk is

greater than normal An even more discriminating

analysis involves measurement of apoprotein B (a

specific protein marker for LDL) to apoprotein A (a

specific marker for HDL) The apoprotein A to

apoprotein B ratio correlates more reliably with the

risk of coronary heart disease than even the ratio of

HDL cholesterol to total cholesterol (See also DIET,

HIGH COMPLEX CARBOHYDRATE.)

high-fat foods See CALORIE; CHEESE; CONVENIENCE

FOOD; FAT, HIDDEN; MEAT

high-fructose corn syrup See FRUCTOSE CORN SYRUP

high oleic oils Vegetable oils that contain a tively high percentage of the monounsaturatedfatty acid, oleic acid This fatty acid contains onedouble bond, unlike polyunsaturated fatty acids.OLIVE OILand certain canola oils are examples

rela-histamine A chemical that triggers INFLAMMATIONand typical “hay fever” symptoms: itching, sneez-ing, hives, runny nose, swelling, heat, and sore-ness Other inflammatory agents are kinins,PROSTAGLANDINS, LEUKOTRIENES, and complement.Histamine is synthesized by many cells, especiallymast cells, which initiate inflammation in connec-tive tissue Basophils (a type of white blood cell)and blood platelets (small cell fragments that assist

in clot formation in vessels) also synthesize mine Histamine release is triggered by scavengercells attracted to the site of injury Histamine makescapillaries leaky, allowing water to collect in theaffected tissue, thus causing swelling; immediatelyafter injury, blood vessels dilate in the area ofinjury The increased permeability permits defen-sive materials in the blood better access to theinjured area

hista-Antihistamines are drugs that block the action ofhistamine and relieve hay fever symptoms ofallergy attacks, but not of colds The use of antihis-tamines poses a number of possible problems Theycan worsen ASTHMA, PEPTIC ULCERS, kidney disease,and glaucoma and can increase difficulty in urina-tion (enlarged prostate) Newer antihistamines donot by themselves usually cause sleepiness Whentaken during pregnancy, some antihistamines maycause birth defects

Antihistamines may also cause blurred visionand drowsiness They can exaggerate drowsinesswhen taken with tranquilizers or alcohol, andsevere sedation can occur if antihistamines are alsotaken with antidepressants, sleep inducers, nar-cotics, cocaine, or marijuana (See also IMMUNE SYSTEM.)

Oken, R J “Antihistamines, a Possible Risk Factor for

Alzheimer’s Disease,” Medical Hypotheses 44, 1 no.

(1995): 47–48.

340 histidine

histidine An AMINO ACIDthat serves as a PROTEIN

building block It is a required nutrient in growing

children and is classified as a semi-essential or

con-ditionally essential nutrient, which must be

sup-plied in the DIET Histidine is classified as an

aromatic amino acid unique among the common

amino acids in its ability to act as a physiological pH

BUFFER A deficiency of histidine can cause ANEMIA

because it is a major building block for HEMOGLO

-BIN, the oxygen transport protein of red blood cells

Other symptoms of histidine deficiency include

FATIGUEand scaly dry skin

Histidine is converted to HISTAMINE, a trigger of

inflammation by mast cells, which fight localized

infections MEAT, FISH, and POULTRYare rich sources

of all essential amino acids, including histidine

(See also AMINO ACID METABOLISM.)

hiziki See SEAWEED

homeostasis Maintaining the body’s internal

environment within well-defined limits that

support life Homeostasis refers to an internal

envi-ronment providing optimal concentrations of

WATER, nutrients, ions, and oxygen; an optimal

temperature; and an optimal osmotic pressure

Homeostatic mechanisms regulate BLOOD SUGAR

concentration and pH, body temperature, blood

pressure, and osmotic pressure STRESS creates an

imbalance within the body External stressors

include loud noises and extreme temperatures;

internal stressors include pain, mental disturbances,

and high blood pressure Stress-induced imbalances

are counteracted by the many homeostatic

mecha-nisms that return the body to balance They

dissi-pate heat and dispose of lactic acid produced during

exercise, for example

Every structure of the body contributes to

main-taining a normal internal environment In

particu-lar, homeostatic responses are controlled by the

nervous system and the ENDOCRINE SYSTEM The

regulation and integration of these two systems is

accomplished by the PITUITARY GLAND, the HYPO

-THALAMUS, and the ADRENAL GLANDS The

hypothal-amus is the region of the brain that controls the

autonomic nervous system, nerves that regulate

the pituitary gland, the “master gland” of the

endocrine system, smooth muscles such as those

around blood vessels, and cardiac muscles Theparasympathetic and sympathetic portions of theautonomic NERVOUS SYSTEM counterbalance eachother The sympathetic division adapts the body tostress, while the parasympathetic division of thissystem restores energy to tissues and restores thebody after stress (See also ADRENAL GLANDS; FEED-BACK INHIBITION; FIGHT OR FLIGHT RESPONSE.)

homocysteine An artery-damaging amino acidproduced as a normal by-product of amino acidbreakdown Homocysteine comes from the essen-tial amino acid, METHIONINE, as it is broken down toform CYSTEINE, another sulfur-containing aminoacid Unlike methionine and cysteine, homocys-teine is not used by the body as a protein buildingblock Instead it is usually recycled back to methio-nine when there are ample B vitamins Accumu-lated evidence links high homocysteine levels inthe blood to an increased risk of heart attack andstroke In one U.S population (the FraminghamHeart Study), nearly one-third of adults 67 or olderhave high blood homocysteine levels In the Physi-cian’s Health Study which followed, approximately22,000 male doctors found that elevated bloodhomocysteine levels, even in the range considerednormal, correlated with an increased risk of heartattacks Hypothetically, homocysteine could injurethe lining of blood vessels (a vascular toxin), itcould increase the production of muscle cells sur-rounding vessels and it could promote blood clots

In another study patients with high homocysteinelevels had nearly twice the risk of developingALZHEIMER’S DISEASE

Usually, the amount of homocysteine in theblood is low However, ENZYMES responsible foramino acid conversions may be deficient in somepeople, while others may not consume enough ofkey vitamins that function as enzyme helpers Inthe Framingham study, two-thirds of the peoplewith high homocysteine do not consume enough

of the B vitamins Especially inadequate intake ofFOLIC ACID VITAMIN B6, riboflavin, and VITAMIN B12can raise blood levels of homocysteine Theoreti-cally, with vitamin deficiencies, enzymes do notoperate efficiently, cellular machinery slows down,and homocysteine backs up and accumulates in theblood Supplementation with folic acid and vitamin

B12 can help reverse the effects of deficiencies,

improve the action of inefficient enzymes, and

lower blood homocysteine It is estimated that

about 400 mcg of folic acid daily can lower

homo-cysteine levels to safe levels Although elevated

blood homocysteine levels correlate with an

increased risk of heart attack, lowering

homocys-teine by B vitamins can improve cardiac

perfor-mance with exercise and reduce the risk of arterial

blockage following angioplasty, according to

lim-ited clinical studies It is not yet proven that

lower-ing homocysteine prevents heart disease, however

Folic acid occurs in dark green vegetables,

includ-ing broccoli and spinach, and in fruits, such as

oranges and apples and in liver (See also CARDIO

-VASCULAR DISEASE; NEURAL TUBE DEFECTS; PROTEIN.)

Motulsky, Arno G “Nutritional Ecogenetics:

Homocys-teine-related Arteriosclerotic Vascular Disease, Neural

Tube Defects, and Folic Acid,” American Journal of

Human Genetics 58 (1996): 17–20.

Seshadri, S et al “Plasma Homocysteine as a Risk Factor

for Dementia and Alzheimer’s Disease,” New England

Journal of Medicine 346, no 7 (February 14, 2002):

476–483.

homogenized milk See MILK

honey A syrupy, sweet liquid obtained from plant

nectar by honey bees Honey contains the simple

sugars FRUCTOSE, GLUCOSE, small amounts of other

sugars, and traces of MINERALSand VITAMINS, though

the quantities are far below the daily requirements

Honey is considered a refined CARBOHYDRATE that

provides only CALORIES, like other NATURAL SWEET

-ENERS Honey is sweeter than table sugar and

con-tains more calories; honey concon-tains 65 calories per

tablespoon, while table sugar supplies 46 calories

The color and flavor of honey depends on the

proportion of sugars and varies with the source of

the nectar In the United States, most honey is

pro-duced from ALFALFAand clover Tupelo honey from

the southern United States contains more fructose

and seldom granulates Honey is used in the baking

industry to keep breads and cakes moist and to

improve the browning quality in baked goods To

substitute honey for table sugar in recipes, liquid

should be reduced by a quarter-cup for each cup of

honey used

Commercial honey is heated to destroy yeasts,then filtered and bottled, while raw honey may beonly strained and bottled Honey has a low pH and

a high osmotic pressure and is not a friendly ronment for bacteria Nonetheless, raw honeyshould not be fed to infants because it may containenough bacterial spores to cause BOTULISM, a type

envi-of FOOD POISONING This does not occur in olderchildren and adults Honey from some types ofrhododendrons, especially in the Pacific Northwestand Northeast, can cause sudden illness, mimicking

a heart attack Symptoms may last up to 24 hours.The recommendation is to use blended honey from

a variety of sources

honeydew melon (Cucum) A member of themuskmelon family, which includes CANTALOUPE, CA-SABA, and other melons Honeydews have a smooth,yellowish-white rind and a sweet, green flesh Thenutrient content for half a melon provides: calories,225; protein, 3.0 g; carbohydrate, 59 g; fiber, 7.0 g;potassium, 1,755 mg; thiamin, 0.5 g; riboflavin, 0.1mg; niacin, 3.85 mg; vitamin C, 160 mg

hormone A chemical messenger sent throughthe bloodstream to target tissues The name hor-

mone is derived from the Greek word hormon,

which means “to set in motion.” The brain andnervous system control hormone release from spe-cialized tissues called endocrine glands, and theENDOCRINE SYSTEM consists of all the hormone-producing tissues They include the HYPOTHALAMUS,the PITUITARY GLAND, ADRENAL GLANDS, endocrinePANCREAS, THYROIDand PARATHYROIDglands, glands

of the stomach and intestine, pineal gland, THYMUS,ovaries, testes, and placenta Each endocrine glandsecretes a characteristic hormone or set of hor-mones Hormones from each source act on a spe-cific target tissue or tissues

The hypothalamus is a region of the brain thatactivates the pituitary gland, known as the mastergland, by means of “releasing hormones.” Thehypothalamus also makes two hormones that arereleased through the pituitary gland: ANTIDIURETIC HORMONE(ADH) decreases the amount of WATERinurine by increasing SODIUMretention in the kidney;OXYTOCINstimulates lactation and uterine contrac-tions for birth

hormone 341