K 378 kabob Chunks of seasoned meat grilled or roasted on skewers. The name comes from the Turkish sis kebab, meaning “skewered, roasted meat.” Traditionally, marinated mutton or lamb is skewered with pork fat or mutton fat. American variations of ingredients include veal, meatballs, and vegetables like onions, peppers, mushrooms, and tomatoes. (See also BARBECUED MEAT.) kale (Brassica oleracea acephala) A dark green, leafy vegetable of the cabbage family that is closely related to the European wild CABBAGE. There are many different leaf forms of kale, from curly to plain, and colors range from bluish-green to red- brown and purple. Kale withstands the stress of cold weather and severe frosts, and gardens can provide fresh greens into autumn. Kale holds its texture when cooked, making it a useful ingredient in soups, meat loafs, stews, and the like. Eaten raw, it can be used in mixed salads. Kale can be blanched, steamed, sauteed, or microwaved. Like other leafy greens, kale contains high levels of BETA-CAROTENE (provitamin A). One cup, cooked (130 g), provides: 42 calories; protein, 3.5 g; carbo- hydrate, 7.3 g; fiber, 3.7 g; calcium, 94 mg; potas- sium, 296 mg; vitamin A, 962 retinol equivalents; thiamin, 0.07 mg; riboflavin, 0.009 mg; niacin, 0.70 mg; vitamin C, 53 mg. (See also CHARD; SPINACH.) karaya gum A FOOD ADDITIVE that serves as a thickening agent and is not absorbed by the INTES- TINE. Karaya GUM, obtained exclusively from the sterculia tree in India, prevents fats and oils from separating in whipped products and salad dressing and in the meat juices in sausages. It also improves the texture of ice cream and has been used as a LAXATIVE. Karaya gum is unique in that it expands to up to 100 times its dry volume when wet. Some individuals are allergic to karaya gum, but it is presumably safer than other thickening agents since little of it is absorbed. However, long-term safety studies have not been performed. The ques- tion of whether this gum binds nutrients and pre- vents their absorption has not been resolved. (See also BULKING AGENTS.) kasha Roasted BUCKWHEAT; a coarse or finely ground, hulled GRAIN that can be cooked like RICE. The roasting process conveys a nutlike flavor. Buckwheat is not a grass, therefore it is not related to the cereal grains. Individuals who are allergic to GLUTEN can often tolerate buckwheat. In the United States, buckwheat is most commonly eaten as an ingredient in pancakes. Kasha is also an eastern European dish. Russian kasha refers to small buck- wheat pancakes. Polish kasha is a sweet pudding prepared either with BARLEY or with SEMOLINA. kava (Piper methysticum, kawa) A plant native to South Pacific islands, where the root of the plant is often ground into the fine paste and used in a tradi- tional ceremonial beverage. It has been sold in the United States as an herbal supplement to ease gen- eralized anxiety, sleeplessness, and anxiety during menopause. In 2002 the U.S. FDA issued a consumer advisory warning that kava-containing products had been associated with liver-related injuries, including hepatitis, cirrhosis, and liver failure in patients tak- ing normal doses for as little as 1 to 3 months. It is therefore not recommended; kava is banned in Switzerland and Germany is considering a ban. kefir Fermented milk. A traditional beverage of the Middle East and southern Russia. Originally, kefir was prepared from camel’s MILK; now cow’s milk is fermented instead of camel’s milk. The fer- mentation process produces LACTIC ACID, which gives kefir its tangy flavor. Fermentation also pro- duces a low level of ALCOHOL (generally about 1 percent). One cup provides 150 calories; protein, 9.3 g; carbohydrate, 8.8 g; fat, 4.5 g; calcium, 350 mg; potassium, 205 mg; vitamin A, 155 mg; thi- amin, 0.45 mg; riboflavin, 0.44 mg; niacin, 0.30 mg. (See also YOGURT.) kelp See SEAWEED. keratin A PROTEIN that is the major constituent of skin, hair, nails, and the protein matrix of tooth enamel. Keratin is a highly insoluble protein, clas- sified as a structural protein. Its role in protecting the body is passive only. Alpha keratin occurs in mammals and consists of highly coiled protein chains that form insoluble fibers. This protein con- tains high levels of the sulfur-containing AMINO ACID , CYSTEINE. The cysteine sulfur atoms of adja- cent keratin chains cross-link with each other, making keratin resistant to stretching and con- tributing to water insolubility and strength of hair. For this reason, keratin also resists digestion. Ker- atin in skin is softer than in hair and nails because it has less sulfur content, and therefore less cross- linking. Toxic HEAVY METALS bind to keratin in hair, and mineral analysis of hair samples can reveal the accumulation of toxic elements like LEAD, CAD- MIUM , or MERCURY. (See also HAIR ANALYSIS.) ketchup (catsup) In North America, a thick tomato sauce used to flavor MEAT, FISH, HAMBURGERS, FRENCH FRIES, and HOT DOGS. Ketchup is made of tomato puree, SALT, VINEGAR, and a variety of spices, Typical ketchup contains 25 percent SUGAR and rep- resents one of the hidden sources of this sweetener, though it is not considered sweet. One tablespoon (17 g) contains 18 calories; protein, 0.3 g; carbohy- drate, 4.3 g; sodium, 156 mg; and trace levels of vit- amins. (See also CONDIMENT; FOOD PROCESSING.) keto acid A class of weak ACIDS with a carbon atom skeleton. The keto acids are more highly oxi- dized acids than FATTY ACIDS and appear as inter- mediates in metabolic pathways of the body, which oxidize fatty acids and CARBOHYDRATES for energy production. Keto acids contain a keto group, an oxidized carbon atom found in a class of organic compounds called ketones. Typical keto acids of cellular METABOLISM in- clude: PYRUVIC ACID (three carbon atoms), produced from the single sugar GLUCOSE by GLYCOLYSIS, the major pathway of glucose degradation. Alpha keto- glutaric acid (five carbon atoms) and OXALOACETIC ACID (four carbon atoms) are intermediates of the KREB ’S CYCLE, the central energy-producing path- way of the cell. Oxaloacetic acid is important for several reasons. It is both the starting point and the end point of the KREB’S CYCLE. Furthermore, oxaloacetic acid can be converted to glucose for BLOOD SUGAR . Keto acids are produced in the degradation of certain AMINO ACIDS by removal of their amino groups (nitrogen-containing groups). Thus, the amino acid ALANINE yields pyruvic acid; ASPARTIC ACID yields oxaloacetic acid; and GLUTAMIC ACID yields alpha ketoglutaric acid. The process is reversible so that an addition of an amino group to pyruvic acid forms alanine; to oxaloacetic acid, forms aspartic acid; an addition to alpha ketoglu- taric acid forms glutamic acid. Because these amino acids are readily synthesized by the body from common keto acids, they are not essential to the diet. (See also AMINO ACID METABOLISM; CARBOHY- DRATE METABOLISM ; GLUCONEOGENESIS.) ketogenic Refers to compounds converted to KETONE BODIES , a kind of metabolic acid, during their chemical breakdown for energy production. Ketogenic compounds include free FATTY ACIDS and the amino acid LEUCINE. Most amino acids are both ketogenic and “glycogenic”; that is, their complex structures are broken down into both ketone bod- ies and the sugar GLUCOSE. Excessive accumulation of ketone bodies may acidify the body, leading to imbalances. (See also ACIDOSIS; AMINO ACID METAB- OLISM.) ketone bodies The water-soluble products of excessive fat breakdown. Ketone bodies represent ACETOACETIC ACID, BETA HYDROXYBUTYRIC ACID, and ACETONE, which are synthesized by the liver. They accumulate in the blood during prolonged fasting, STARVATION, crash DIETING, and ALCOHOLISM. Each of these conditions promotes high rates of fat degra- ketone bodies 379 dation. Fatty acids cannot be completely oxidized for energy under these conditions and are instead converted to ketone bodies. The accumulation of ketone bodies in the blood and their excretion in the urine indicates a potentially hazardous meta- bolic imbalance. (See also ACIDOSIS; FAT METABO - LISM ; KETOSIS.) ketosis The accumulation of KETONE BODIES in the blood due to incomplete oxidation of FATTY ACIDS . Excessive fat breakdown can occur during uncontrolled diabetes, ALCOHOLISM, crash DIETING, and with high-fat, low-carbohydrate diets. Pro- longed high levels of ketone bodies ( ACETOACETIC ACID and BETA HYDROXYBUTYRIC ACID), can acidify the blood ( ACIDOSIS). Furthermore, ketone body excretion in the urine can lead to excessive water loss (starvation diuresis). DEHYDRATION is poten- tially hazardous. Ketosis causes disturbances in ELECTROLYTES (dissolved minerals like SODIUM, POTASSIUM, and CHLORIDE) in body fluids. Imbal- anced electrolytes can alter heart function and ner- vous system responses. Severe ketosis can cause coma and, ultimately, death. kidneys Organs that regulate the amounts of key ingredients in blood, including WATER, the pH (acid- ity) and the levels of minerals ( ELECTROLYTES ), and in excreted waste products. By regulating water excretion in urine, kidneys also regulate BLOOD PRESSURE . There are two kidneys, located close to the backbone at the back of the abdomen. Each is about 4 in. (10 cm) long and each contains approx- imately one million filtering units called NEPHRONS, resembling small tubes. The nephrons filter a huge amount of fluid; about 425 gallons (1,930 liters) per day for adults. However, only a very small fraction, (2 liters) is excreted as urine, because most of the water, and most of the other useful blood con- stituents, are reabsorbed and recycled. Nephrons are supplied with blood from the kidney artery, and a small cluster or “tuft” of capil- laries (glomerulus) feeds each nephron. The glo- merulus acts as a filter under pressure. The filtrate, the fluid emerging from the glomerulus, contains small molecules like water, salts (dissolved miner- als, SODIUM, POTASSIUM, CHLORIDE), GLUCOSE, UREA (the end product of protein degradation), and cre- atinine (the waste product of muscle metabolism). Larger particles like proteins and cells are retained in the blood by the glomerulus. The filtrate passes through the convoluted tubules of the nephron, where most of the sodium chloride is reabsorbed into the blood. The tubules help regulate the sodium content and the pH of the blood by exchanging electrolytes like AMMONIA, potassium, and chloride. The final product is urine. Glucose at normal blood concentrations is com- pletely reabsorbed by the kidneys into the blood. In DIABETES MELLITUS the blood sugar concentration may be so high that more glucose appears in the fil- trate than can be reabsorbed, and thus it passes into the urine (glucosuria). Because water follows the glucose, frequent urination accompanies glucose in the urine and may cause DEHYDRATION. Certain metabolic acids called KETONE BODIES may accumu- late in the bloodstream with ALCOHOLISM, untreated diabetes, crash DIETING, and other situations. Once their levels exceed the kidney threshold, ketone bodies are excreted in the urine. This, too, can cause dehydration and electrolyte imbalances that further compromise the patient’s health. Urine represents the concentrated waste; 99 percent of the water has been reabsorbed by the time urine reaches the ureters, which are tubes that drain into the bladder. The kidneys regulate water balance. If there is too much fluid in the body, the kidneys excrete more water as urine. When there is too little fluid, they retain more water and urine becomes more concentrated. Envi- ronmental temperature also affects kidney function because sweating increases water losses, prompting the kidneys to retain more water. Kidneys add potassium and hydrogen ions, ammonia, and bicar- bonate to the filtrate to control blood pH. HORMONES regulate kidney function. Water retention can be regulated by a pituitary hormone, ANTIDIURETIC HORMONE (ADH). Release of this hor- mone is stimulated when the brain ( HYPOTHALA- MUS) detects a low blood-water concentration. ADH increases water loss from cells, allowing more water to pass back into the blood. ALDOSTERONE,a hormone from the adrenal glands, regulates sodium excretion. If the sodium level drops, for example from sweating or DIARRHEA, aldosterone levels increase, salt reabsorption from the filtrate increases, and water is retained. 380 ketosis The kidneys also process hormones. VITAMIN D is activated by the kidneys; they convert calcidiol (25-hydroxyvitamin D) to the hormone calcitriol (1,25 dihydroxyvitamin D). They also produce ery- thropoietin, a hormone that stimulates BONE mar- row to produce RED BLOOD CELLS , and renin, a hormone that controls blood pressure. (See also BLADDER INFECTIONS; GLOMERULAR FILTRATION; KID- NEY STONES .) kidney stones Mineralized particles occurring in the kidney and upper urinary tract. Most kidney stones contain CALCIUM as carbonate, phosphate, or oxalate. In the United States, they are quite com- mon and more prevalent than stone formation in the gallbladder. An estimated 10 percent of men and 15 percent of women over 30 years of age will eventually develop kidney stones. A kidney stone is formed when the concentra- tion of mineral salts in urine increases to the point of saturation, at which time the mineral will spon- taneously crystallize. DEHYDRATION and increased calcium in urine favor stone formation. High uri- nary calcium can reflect a high intake of VITAMIN D, too much ALUMINUM or MILK, overactive THYROID (hyperthyroidism), lengthy immobilization, or kid- ney disease. Calcium oxalate stones are more likely with vitamin B 6 deficiency; with high consumption of foods like SPINACH rich in the organic acid OXALIC ACID ; intestinal disease (particularly of the ileum); fatty stools; and abnormal metabolism of certain organic acids. Possible Causes Certain metabolic diseases, such as parathyroid malfunction and certain diseases of the bone, can cause kidney stones. MILK ALKALI SYNDROME is asso- ciated with an increased risk. Many toxic metals, especially CADMIUM, increase the risk of stone for- mation. In addition, several dietary factors are often linked. Inadequate water intake prompts the formation of insoluble salts. Inadequate VITAMIN K could promote stone formation because the vita- min assists in the synthesis of a protein that inhibits stone formation. INSULIN insensitivity and OBESITY increase the risk of stone formation. Certain foods contain high oxalic acid levels; therefore, reduced intake of COCOA, tea, spinach, chard beet leaves, RHUBARB, and PARSLEY decreases the risk. Consum- ing more FIBER-rich foods, like fruit and vegetables, is likely to decrease the risk of kidney stones. VITA- MIN B 6 deficiency is also linked to oxalate-stone for- mation. URIC ACID occasionally forms stones, a process favored by the excessive consumption of nucleic acid-rich foods like yeast and organ meats, and by certain anticancer drugs. The prevention of kidney stones relies on dietary changes: • Drinking plenty of water. Adequate water is needed to keep salts dissolved. • Avoiding sugar, refined carbohydrate, and excessive animal protein, salt, and caffeine. These tend to increase the level of calcium in urine. • Avoiding cola soft drinks. These contain phos- phate, which promotes stone formation. • Avoiding over-consumption of aluminum con- taining antacids. • Minimizing alcohol consumption. High alcohol consumption favors dehydration. • Emphasizing magnesium-rich foods. Magne- sium deficiency is linked to kidney stone forma- tion, so eating foods with a high magnesium content—barley, wheat bran and other whole grains, avocados, bananas and lima beans—or supplements can reduce the risk. • Citric acid keeps calcium solubilized, and citric acid supplementation has been used to reduce the incidence of kidney stones. (See also GALLSTONES.) Burtis, William J. et al. “Dietary Hypercalciuria in Patients with Calcium Oxalate Kidney Stones,” Amer- ican Journal of Clinical Nutrition 60, no. 3 (September 1994): 424–429. kilocalorie A measure of ENERGY content fre- quently used in nutrition. The term CALORIE is fre- quently used synonymously with kilocalorie although strictly speaking it should be capitalized (Calorie). The prefix “kilo” means 1,000. Thus, one kilocalorie (abbreviated kC.) is the amount of heat required to increase the temperature of 1,000 g(1 l) of water by 1° C (from 15.5° C to 16.5° C), while a calorie (small c.) refers to heating 1 g of water by 1° C. The caloric content of foods and daily energy kilocalorie 381 requirements are given in kilocalories. A small calo- rie is one-thousandth of a kilocalorie. However, the international standard for energy content is based on the JOULE; 1 kilocalorie equals 4.18 kilojoules. kiwi fruit (Actinidia chinensis) An egg-sized fruit that originated in China and is now cultivated in New Zealand, France, Israel, and California. Kiwi fruit has a thin, brown, hairy skin. The fruit is pale green with a tangy taste and is eaten raw, used in fruit salads and tarts or as a garnish with meat and fish. Each raw fruit (46 g, peeled) provides 46 calo- ries; protein, 0.8 g; carbohydrate, 11.3 g; fiber, 1.16 g; calcium, 15 mg; potassium, 80 mg; vitamin C, 31 mg; thiamin, 0.02 mg; riboflavin, 0.01 mg; niacin, 0.06 mg. kohlrabi (Brassica oleracea, var. caulorapo) A stem vegetable of the CABBAGE family. Its bulbous stalk (resembling a turnip) distinguishes its appear- ance from other members of the cabbage family. Kohlrabi was popular in the Middle Ages in central and eastern Europe. Currently, kohlrabi is grown in California. Kohlrabi is a source of VITAMIN C, CAL- CIUM, and IRON. Small stems are more tender than the more mature vegetable. It is cooked like a turnip or celery root. Cooked, sliced kohlrabi (1 cup, 165 g) provides 48 calories; protein, 3 g; car- bohydrate, 11.4 g; fiber, 2.3 g; calcium, 50 mg; iron, 0.66 mg; potassium, 561 mg; vitamin C, 89 mg; thi- amin, 0.07 mg; riboflavin, 0.03 mg; niacin, 0.64 mg. (See also CELERIAC.) kombu See SEAWEED. konjac (Amorphophallus konjac) A tuber culti- vated in the Far East that is a traditional ingredient in Japanese cooking. The tuber is processed to yield a light-colored flour. Konjac has been used to make noodles (shiritaki noodles) and heat-stable gels such as mitsumame, a fruit dessert. The flour is used in food processing as a thickener for soups, sauces, and desserts. Konjac flour provides a form of FIBER, a complex carbohydrate called GLUCOMAN- NAN that forms viscous solutions in water. When added to processed foods, konjac helps other plant- based thickeners like CARRAGEENAN, XANTHAN GUM, and CORNSTARCH work more efficiently. (See also FOOD ADDITIVES; PASTA; THICKENING AGENTS.) kosher Foods permitted by Jewish law. Jewish dietary laws, known as kashruth, define the fitness and appropriateness of foods. Acceptable and unac- ceptable foods fall into three food groups: Milchig refers to dairy products and MILK; fleishig refers to MEAT , fowl, and products derived from them; and pareve refers to foods that can be eaten with either milk or meat. These neutral foods are FRUITS, VEG- ETABLES , GRAINS, FISH , and EGGS. Acceptable fish have fins and scales; SHELLFISH are excluded. Domestic fowl are permitted, as are animals with a split hoof that chew cud, a group that includes cat- tle, goats, sheep, and deer. Pigs (pork) are not acceptable. CONVENIENCE FOOD is not kosher unless certified by rabbinical authority, signified by the name and insignia on the package. BREAD must be baked by observant Jews under rabbinical supervi- sion. Bread is normally a pareve food. All meat and fowl must be killed according to prescribed methods. Kosher slaughter involves the use of a sharp knife to quickly sever the carotid arteries, jugular bone, and windpipe of a live ani- mal by a trained slaughterer (schochet). Kosher slaughter of poultry must also be done by hand. Some Jews follow a stricter interpretation of rules concerning acceptability. Glatt kosher meat means the organs, especially the lungs of kosher-killed animals, have been inspected for blemishes or defects. Glatt kosher meat and must be soaked and salted within 72 hours of slaughter. GRAPE JUICE and WINE, traditionally used in reli- gious ceremonies, must be prepared by observant Jews. To be kosher, grape juice must be properly separated and heated. If grape-flavored sodas with real fruit juice are not prepared in this way, the soda is not kosher. The Union of Orthodox Jewish Congregations of America has published guidelines regarding the kosher status of food and beverage ingredients. Jews who keep kosher may not eat insects. This poses a problem for fresh produce, especially green, leafy vegetables, which may require inspection. Aphids are a common problem, and fresh produce from health food stores and roadside outlets requires inspection. 382 kiwi fruit The Passover holiday has additional kosher requirements extending over an eight-day period. Many products, kosher for the rest of the year, are not kosher for Passover. Leavened grain and related materials are avoided to commemorate the departure of the Jews from Egypt. Legumes, corn, rice, and mustard are not eaten during Passover by Jews of European ancestry. To separate meat and dairy, the kosher kitchen employs two sets of pots, pans, dishes, utensils, and table linen to be used separately for dairy and meat. Pareve foods can be prepared and eaten with either set. The utensils are washed and stored sep- arately. Currently, an estimated 500,000 families in the United States and perhaps 50,000 families in Canada abide by kosher dietary laws. Some non- Jewish groups, such as Seventh Day Adventists and Muslims, sometimes purchase specific kosher foods to meet their religious needs, and some consumers consider the kosher seal an indicator of quality. (See also EATING PATTERNS.) Kreb’s cycle (citric acid cycle, tricarboxylic acid cycle) A branch of metabolism consisting of a coordinated sequence of enzymes that operate in a cyclic fashion to oxidize the major fuels of the body to produce ENERGY . The Kreb’s cycle is a major METABOLIC PATHWAY and produces approximately 90 percent of the body’s energy production by oxidiz- ing FATTY ACIDS , AMINO ACIDS, and CARBOHYDRATES to carbon dioxide. The Kreb’s cycle occurs in MITO- CHONDRIA , particles in the cell’s cytoplasm that function as cellular powerhouses. Prior to entering the Kreb’s cycle, fuel molecules are broken down to ACETIC ACID, a two-carbon mol- ecule that is attached to a carrier molecule called COENZYME A. The product, ACETYL COENZYME, feeds into the Kreb’s cycle. The acetic acid unit (two car- bon atoms) combines with a simple acid with four carbon atoms, OXALOACETIC ACID, to create CITRIC ACID (six carbon atoms), the first true product of the Kreb’s cycle. Subsequent oxidations release carbon dioxide and regenerated oxaloacetic acid, which can again react with incoming acetyl COA to continue the cycle. Certain B complex VITAMINS support energy pro- duction from food in part because they assist the Kreb’s cycle. They include NIACIN, RIBOFLAVIN, PAN- TOTHENIC ACID, and THIAMIN. B vitamins must first be converted to a COENZYME or enzyme helper to catalyze chemical reactions performed by the cycle. Thus, coenzyme A is the coenzyme form of pan- tothenic acid. The Kreb’s cycle is coupled with other pathways supporting energy production by mitochondria, the cell’s powerhouses. Coenzymes of niacin and riboflavin, as well as COENZYME Q, carry electrons from the oxidations of the Kreb’s cycle to the ter- minal ELECTRON TRANSPORT CHAIN, which reduces OXYGEN to form WATER and simultaneously forms ATP, the cell’s energy currency. When the Kreb’s cycle slows down, this slowdown inhibits glucose oxidation, allowing it to be shunted to storage mechanisms by the liver. (See also CARBOHYDRATE METABOLISM ; FAT METABOLISM.) Barron, John T., Stephen I. Kopp, and June Tow. “Fatty Acid, Tricarboxylic Acid Cycle Metabolites and Energy Metabolism in Vascular Smooth Muscle,” American Journal of Physiology 267 (August 1994): Part 2, H764–H769. kudzu (Pueraria lobata) A fibrous root vegetable, native to subtropical Asia; kudzu is used as a source of complex carbohydrate. It is chopped into cubes and cooked with soups in order to thicken them, and is available in Asian food markets. The food value, in 100 g (raw) is: calories, 120; protein, 2.1 g; carbohydrate, 27.8 g; fiber, 0.7 g; and essentially no fat. (See also STARCH.) kumquat (Fortunella spp.) A small CITRUS FRUIT, with a sweet rind and a sour pulp. Kumquats are about the size of a quail’s egg and have a thin, orange-red skin that is eaten with the fruit. Kumquats originated in China and are now culti- vated in Australia, the Far East, Florida, and Cali- fornia. Kumquats can be eaten raw with skins, in jam and in baked goods like cakes. Nutrient content of one fruit (raw, 20 g) provides 12 calories; protein, 0.17 g; carbohydrate, 3.1 g; fiber, 0.7 g; vitamin C, 7.1 mg; thiamin, 0.02 mg; riboflavin, 0.02 mg. kwashiorkor A severe malnutrition disease caused by a chronic protein-deficient diet. Kwash- iorkor is the classic protein deficiency disease in kwashiorkor 383 which caloric intake may be adequate, but con- sumption of too little PROTEIN causes serious MAL- NUTRITION. Protein and ENERGY are required for growth and maintenance of the body. People con- suming too little food to supply either will degrade their own body protein and fat. Thus, protein malnutrition and energy malnutrition overlap. Symptoms include EDEMA, apathy, decreased resis- tance to disease, delayed development, depig- mented hair, and scaly skin. Symptoms in children include bloated belly, DIARRHEA, fatty liver, and ANEMIA . Kwashiorkor is more common in developing tropical and subtropical nations. In low socioeco- nomic regions of Africa, the Near East, Asia, and Central and South America, the disease often be- gins with the birth of a second child. The weaned, first-born child must then rely on cereals, often a protein-deficient diet within the community. This does not supply enough amino acids to maintain a child, nor to support growth. It can be prevented by diets providing adequate protein and energy to meet the child’s growth requirements. (See also BALANCED DIET ; HUNGER, WORLD ; STARVATION.) 384 kwashiorkor . bluish-green to red- brown and purple. Kale withstands the stress of cold weather and severe frosts, and gardens can provide fresh greens into autumn. Kale holds its texture when cooked, making. This protein con- tains high levels of the sulfur-containing AMINO ACID , CYSTEINE. The cysteine sulfur atoms of adja- cent keratin chains cross-link with each other, making keratin resistant. regions of Africa, the Near East, Asia, and Central and South America, the disease often be- gins with the birth of a second child. The weaned, first-born child must then rely on cereals, often