Sodium, Vitamins and Minerals

Transcription

1 Chapter 12 Sodium, Vitamins and Minerals First, we ll discuss vitamins. Vitamins are chemical substances needed in small amounts by the body. With exception of vitamins D and K, the body cannot synthesize its own vitamins and must get them from food sources or supplements. There are thirteen known vitamins. Water soluble vitamins are the eight members of the B complex, plus vitamin C. They do not require fat absorption or transport and, for the most part, are not stored in the body. Once the body tissues have enough of the water soluble vitamins, excesses are excreted in the urine. Because they are continually being used in the body and can t be stored, these vitamins need to be supplied daily. Food Sources Vitamins are found in varying amounts in different foods. No one food is expected to meet all the vitamin requirements. Instead, a variety of foods eaten on a daily basis should provide your vitamin needs. Each food group provides contributions to your daily requirements. For examples: Grains provide thiamin, niacin, and riboflavin. Meats, poultry, and fish are good sources of niacin, B6, B12, and thiamin. Milk supplies riboflavin and vitamin D. Fruits and vegetables provide vitamins A and C. Preventing Vitamin Losses Vitamins are subject to losses due to storage, processing, or cooking; vitamin C, thiamin, and riboflavin are more susceptible than others. To minimize vitamin losses, the following guidelines should be used: Keep milk out of direct sunlight or bright light. Use raw vegetables as soon as possible after preparation. Do not expose cut surfaces of foods to air for extended periods. Cook in only small amounts of liquid. Do not use baking soda in cooking water. Cook foods only until tender. Serve foods promptly after preparation. Use fresh vegetables whenever possible and use fresh vegetables promptly after purchase. Do not wash rice before cooking.

2 In the past, vitamin deficiencies were common because of the limited availability of a varied diet. With the increased availability of a wide variety of foods, deficiencies are much less common today. Today there is an increasing concern about problems associated with excess of vitamins rather than deficiencies. As a result of vitamin hucksters, media distortions, as nutrition experts, many people falsely believe that they need large quantities of vitamins. Others believe in the adage if some is good, more must be better. As a result of vitamin mega does, problems associated with excess intakes are becoming more prevalent. Scientists previously thought these problems only occurred with the fat soluble vitamins, since they are stored and build up in the body; but evidence now shows that it s possible to develop problems from long term, excessive intake of some water soluble vitamins. Besides being potentially dangerous, large amounts of water soluble vitamins are also a waste of money. Since the body doesn t store these, excesses literally go right down the toilet. Vitamin Supplements Are vitamin supplements necessary? In most cases, when a well-balanced diet is consumed, they re not. As mentioned previously there may be instances, when dietary intake is inadequate, or conditions exist that interfere with the intake or proper use of vitamins. Research indicates that the following people may have an increased need for some vitamins: Pregnant or nursing women. Heavy smokers. Woman on oral contraceptives. Heavy drinkers. Users of certain prescription or over the-counterdrugs. People with chronic infections, cancer, or chronic loss of red blood cells. People with genetic disorders or diseases causing problems with vitamin absorption or metabolism. People with increased needs due to surgery, injury, fractures, or burns. Self-diagnosis and therapy of suspected vitamin deficiencies can be a waste of money and potentially dangerous. If your doctor determines that you do have a need for vitamin supplementation, he or she should be the one prescribing it. Employees in health food stores are not qualified to diagnose or treat deficiencies.

3 Minerals Is taking a daily multiple vitamin supplement harmful? Probably not, as long as it contains no more than 100% of the RDA s. Such a supplement can act as insurance against minor dietary inadequacies. I cannot stress the fact too strongly that I have seen a more problems in my professional career from over use of vitamin + mineral supplements than a lack of vitamins. Use a one a day multiple vitamin and mineral like Centrum A-Z if you like that is more than adequate even if diet is poor. Now let s move to minerals. The macro minerals are those that the body needs in relatively large amounts: calcium, phosphorus, magnesium, potassium, sulfur, sodium, and chloride. The micro minerals, also known as trace elements, are minerals that are needed in very small amounts. These include iron, zinc, selenium, manganese, molybdenum, copper, iodine, chromium, fluorine, and cobalt. Research may eventually prove that some of these minerals are essential. Functions of Minerals Minerals have a vast array of functions within the body. Among the many functions are the following: Provide structure and hardness to the bones and teeth. Combine with proteins to form cell structures, hemoglobin for oxygen transport, and enzymes. Regulate nerve impulse transmission and muscle contraction. Keep the proper amount of fluid in and around cells. Maintain the balance between alkalinity and acidity of body fluids. Like vitamins minerals do not provide energy. Instead, some minerals perform essential functions in producing energy from proteins, carbohydrates, and fats. Plants get minerals from the soil they are grown in, and animals get them from the plant foods they ingest. Although there may be variations in the mineral content of soils causing differences in a food s mineral content, eating a variety of foods will give you all the minerals your body needs. Foods that have been highly processed or refined are an exception to this. During the processed or refined are an exception to this. During the processing and refining, many of the minerals present in the raw product are lost. Examples are: sugar, cornstarch, and products made from refined white flour. You might be saying, but I thought flour was enriched. True, but while most white flour is enriched with thiamin, niacin, riboflavin, and iron, it is not enriched with other trace elements lost in the refining process.

4 Another exception to the abundance of minerals in foods is iron and calcium. Besides being present in a limited variety of foods, both of these minerals are subject to being bound up by other substances in food. For example, the oxalic acid in spinach ties up both calcium and iron, so they are not available for use in the body. The most abundant sources of calcium are dairy products. Calcium is present in other foods, but in much smaller quantities. Getting the U.S.R.D.A of 800 mg per day without consuming milk products would require a rather large intake of other foods. As you can see from the list of calcium-rich foods, some of these other sources such as sardines, oysters, collard greens, ad mustard greens are not among the most popular foods in the United States! Milk is not only an excellent source of calcium, but the lactose naturally present in milk and the added vitamin D help increase calcium absorption. If you are lactose intolerant you might need calcium a couple of times a day or one Citrical will should be enough orange juice with added calcium is also very good. Iron is present in both animal and plant sources, but the iron in animal sources is better absorbed than that from plants. Approximately 15-30% of animal iron is absorbed, but only 5% of plant iron make it into your body. Even with a well-balanced diet, iron content averages only about 6 mg per 1000 calories. This means that to meet the RDA for iron, women of childbearing age would have to consume approximately 3000 calories per day. Considering that most

5 women don t come near this figure, it s not surprising that American women suffer from irondeficiency anemia. Minerals Deficiencies Since most minerals are present in many foods, deficiencies are not widespread. The abovementioned iron-deficiency anemia is the most common nutritional deficiency in the United States. It is most often found in infants, pre-school children, adolescents, and women of childbearing age. Osteoporosis is another deficiency. It is a thinning of the bones caused by a loss of calcium. Did you ever wonder why people get shorter as they get older? It s because calcium leaves the spine, causing it to compress. Loss of calcium is also the reason for the large number of hip and wrist fractures seen in elderly women. There are several factors associated with the development of osteoporosis, including dietary calcium intake, exercise, and the hormone estrogen. Research continues to determine how best to prevent this disease. For now, evidence suggests that an adequate calcium intake throughout life, regular weight bearing exercise, and estrogen replacement after menopause are the best defense. Excess Intakes Like vitamins, minerals also present problems associated with excess intake. These problems have escalated in recent years due to media publicity and health foods stores. Excessive intake of one mineral can cause a shortage of another mineral. For instance, an excessive intake of phosphorus can lead to a deficiency of calcium, even if you re getting an adequate calcium intake. An excess of iron can cause serious problems such as liver, pancreas, or kidney damage. Some of the trace minerals are also poisonous if taken in large quantities. Mineral Supplements Again, the question comes up, is a supplement necessary? In the case of iron, individuals at a high risk of developing iron-deficiency anemia, would benefit from a supplement containing 100% of the RDA, especially if the calorie level is not sufficient to supply iron needs. People who don t drink milk or get adequate calcium from other food sources might also benefit from a supplement. In this case, it s best to ask your pharmacist for suggestions on calcium supplements, since some are not absorbed as well as others. A well-balanced diet should provide sufficient amounts of other minerals, but taking a supplement containing no more than 100% of the RDA (although it may not be necessary) is probably not harmful.

6 Increasing Mineral Intake Most minerals are stable in foods, but some are subject to cooking losses. To get the best mineral intake from food, follow the guidelines for retaining optimal vitamin nutrition. Additionally, the following tips can increase mineral intake: Whenever possible, choose whole grain products over refined ones. Eat a source of vitamin C with a source of iron to increase absorption. For example, meat potatoes or cereal with orange juice. Cook in iron pots to increase iron intake. Sodium Sodium is a mineral that has a unique distinction. Instead of worrying about getting enough, just the opposite is true. Most Americans consume 20 to 25 times more sodium than is actually required by the body. Why is there concern about sodium? Because research shows that high-sodium intakes are associated with increased risks for developing high blood pressure or hypertension; and high blood pressure is linked to serious health problems such as stroke, kidney disease, and heat disease. About 20%, many are sensitive to high-sodium intakes. It s interesting to note that in cultures where sodium intake is very low, there is also very little high blood pressure and the incidence of hypertension does not increase with age as it does in the United States. On the other hand, in Japan where sodium intake is very high, hypertension and its resulting problems are the leading cause of death and disability. Should everyone be concerned with sodium, or just people with high blood pressure? The problem is that it s hard to know if you re susceptible to developing high blood pressure later in life. For this reason, the government suggests that all Americans should avoid too much sodium and the Food and Nutrition Board sets a safe and adequate intake at mg per day. Considering that the body s physiological need is only about 250 mg per day, this recommendation gives you a wide safety margin. Dietary Sources of Sodium Sodium is present in a wide variety of food. It occurs naturally in most foods, with the exception of fruits, which are mostly sodium free. About one-third of the sodium in the typical American diet comes from natural sources. Another one-third comes from processed foods, and the remaining one-third from salt added to food in cooking or at the table. With the increased use of convenience foods and more meals being eaten in fast food establishments, the amount of sodium from processed foods may be even higher.

7 Salt is used, not only as a flavor enhancer, but also as a preservative and texturizer in some food products. The words, salt and sodium, are often used interchangeably, but salt actually consists of 40% sodium and 60% chloride. Its presence in food is evident because of its flavor; however, there are other foods that don t taste salty, but are higher in sodium than saltytasting foods. For instance, a half cup of instant chocolate pudding with 404 mg of sodium than two 1-ounce bags of potato chips with 382 mg. If you look at food labels, you ll see several sodium compounds such as sodium bicarbonate, monosodium glutamate (MSG), and sodium nitrite. But looking for the word sodium isn t always helpful, because additives such as sodium saccharin, di-sodium phosphate, sodium alginate, sodium propionate, and sodium benzoate don t contain a great deal of sodium. Also, some ingredients that contain sodium such as baking powder, baking soda, hydrolyzed vegetable protein, and soy isolates don t list sodium in their names. Further complicating the issue is the fact that sodium-containing ingredients may only contribute a little sodium if used in very small quantities. Since 1986, the government has helped consumers somewhat by requiring sodium content to be listed when a label has a nutritional breakdown. Unfortunately, not all food products have these labels. How can you cut down on your sodium intakes? Here are some hints: In general, make foods from scratch instead of using processed or convenience foods. Gradually decrease the amount of slat used in cooking and at the table. Use fresh or frozen vegetables rather than canned. Make your own TV dinners instead of buying prepared ones. Avoid canned or packaged soups and sauces. Decrease your used of condiments and seasonings such as soy sauce, garlic salt, onion salt, bouillon, pickle relish, and MSG. Experiment with herbs and spices as flavoring agents. Avoid processed meats and cheeses. Avoid Fast foods.

8

9