Essential Nutrients

Here are some facts about the vitamins and minerals essential to your health.

Protein

Do men need more protein than women?

Men and women have about the same need for protein. When the need is expressed as the amount of protein per pound of body weight, however, men, generally being heavier, “need” more protein.

The Recommended Daily Allowances for protein may be used as a guide, although the RDA represents desirable goals in nutrition, not necessarily need.

The allowance for adults is a little more than 0.9 gram of protein per 2.2 pounds of weight. Thus a 154 pounds adult male should have an allowance of 65 grams per day, while a 128 pounds female would have an allowance of 55 grams. Ten additional grams per day are recommended for women during pregnancy, and 20 additional grams during lactation.

Does protein improve the growth and texture of hair?

Certain dietary conditions result in impaired hair development. A true protein deficiency such as kwashiorkor, which is found among children in less well-developed areas of the world, results in striking changes in the hair.

The child’s hair becomes thin and brittle and loses its pigmentation. Once the minimum protein requirements are met, however, additional protein will not affect hair growth and characteristics.

Reference: Academy of Nutrition and Dietetics

Fats

Much confusion has occurred over terms such as cholesterol, saturated, unsaturated, and polyunsaturated when applied to salad and cooking oils, margarine and shortening. What do these terms mean?

Cholesterol is a complex fat-like product found in animal tissues. It is not contained in fats and oils made from vegetable sources.

The other terms describe the chemical nature of fats and oils and can be defined as follows:

  • Saturated fats have all bonds in their carbon chains filled with hydrogen and are usually solids. Animal fats are generally saturated fats.
  • Unsaturated fats have bonds on the carbon chains which are not filled with hydrogen and which attach themselves to the next carbon atom, forming double bonds. Unsaturated fats are usually liquids and are generally derived from vegetable sources such as soybean, corn, and peanut oils.
  • Polyunsaturated fats are unsaturated fats having two or more bonds in the carbon chains which are not filled with hydrogen. Polyunsaturated fats are usually liquids and are produced from vegetables.

Vitamin A

What is a good source of vitamin A?

Vitamin A is present in milk, butter, margarine, and many other foods. Carotene, which is converted to vitamin A, is very abundant in nature as a yellow pigment found in carrots, pumpkin, and squash.

Parents should make certain that their children receive adequate amounts of vitamin A, but should avoid giving them massive doses.

Is it harmful to take vitamins A and C in large quantities?

Massive doses of vitamin A can accumulate and cause serious body damage. (It should be noted that vitamin D, taken in large quantities for a prolonged period of time, can be harmful, also.) There are no known hazards in taking large doses of vitamin C; however, there are no known advantages, either.

Vitamin B

Is there a vitamin which prevents grey hair?

No known remedy has been discovered to date that will prevent the graying of hair. When it was found that pantothenic acid, a B vitamin, would prevent grey hair in certain strains of laboratory animals on deficient diets there was great hope that it would work similarly in humans. Unfortunately, it did not. There is as yet no evidence that nutrition plays any role in the graying of hair.

Vitamin C

Does vitamin C prevent colds?

No specific vitamin or vitamins will prevent or cure a cold. There is no evidence to support the contention that vitamin C is more beneficial than any of the other vitamins. Good nutrition will certainly aid resistance to colds and other infections, although no one vitamin or nutrient will prevent or cure them.

Are citrus fruits the only source of vitamin C?

Citrus fruits, tomatoes, melons, berries, broccoli, brussels sprouts, cabbage, asparagus, and cauliflower all contain vitamin C. One serving per day of one of these foods will provide all the vitamin C needed, and no supplemental source is necessary.

Vitamin C, usually in the form of orange juice, is given daily to infants as soon as artificial bottle feeding is instituted. This is perhaps the only situation in which vitamin C is added to the human diet. Special attention also is given to vitamin D during infancy and childhood.

What is the relationship between vitamin C requirements and cigarette smoking?

Recent studies have indicated that the blood concentration of vitamin C is lower in smokers than in non-smokers. Smokers were found to retain more vitamin C, when large doses were given, than non-smokers. Retention of a high proportion of the test dose suggests low tissue stores of the vitamin.

A study of guinea-pigs, who were exposed to tobacco smoke, revealed that the vitamin C content of the adrenal glands had been reduced and that the guinea pigs gained weight less rapidly than another group who had not been exposed to smoke. It is not known whether the increased requirement for vitamin C is due to increased excretion, inefficient utilization, impaired absorption, or multiple causes.

Vitamin D

What are the best sources of vitamin D?

Sunlight activates vitamin D precursors in the skin, resulting in a highly dependable, though variable, additional source of the vitamin. The actual dietary need is therefore dependent upon the amount of exposure one has to sunlight.

Vitamin D is found in very moderate amounts in a few foods such as eggs, some salt-water fish, and milk.

Niacin

The Recommended Dietary Allowance for niacin is listed in niacin equivalents; what does this mean?

The requirement for niacin can be expressed directly in milligrams (mg), but not all of the niacin ultimately available to the body is preformed. The amino acid tryptophan can be converted into niacin. The conversion is such that 1mg of niacin is derived from each 60mg of tryptophan. Accordingly, the absolute requirement for preformed niacin depends upon the amount of tryptophan in dietary protein.

Vitamin E

Is it true that muscular dystrophy is caused by lack of vitamin E in the diet? What are the functions of vitamin E in the body?

Enthusiastic claims have been made for the therapeutic effectiveness of vitamin E in relieving or preventing conditions such as muscular dystrophy, rheumatic fever, toxemia of pregnancy, and cardiovascular diseases. These claims, however, have not been substantiated. Recently, it was found that a particular anemia in children responded to vitamin E therapy.

It is generally agreed that vitamin E functions as a biological antioxidant, preventing the unwanted oxidation of certain fatty acids and fat-soluble compounds in the body and in foods. For this reason, it is important to have an adequate amount of vitamin E in diets that include large amounts of polyunsaturated fatty acids.

Fortunately, the vegetable oils that serve as important sources of these fatty acids contain large amounts of the vitamin. Foods which are considered good sources of vitamin E are wheat-germ oil, green leafy vegetables, legumes, and nuts. Lesser amounts are found in eggs and meat.

Reference: Antioxidant Vitamins

Iron

Do newborn infants need iron supplements?

The normal infant is born with enough iron stores to supply his needs for approximately 3 months, if his mother’s diet has been adequate prior to and during pregnancy.

At 3 months, the pediatrician recommends the introduction of solid or semi-solid, iron-rich foods, such as strained meats, egg-yolk, and specially prepared infant cereals fortified with iron. Growing children require a consistently adequate iron intake.

Meat, eggs, green vegetables, beans, nuts, and whole-grain and enriched cereals are the best sources of iron. Iron from cookware and from soil adhering to foods also can be a major source of iron.

Calcium

Does too much calcium in the diet cause calcium deposits in the joints or arthritis in older people?

A lowered calcium intake in adults has been indicated recently as a possible factor in the development of osteoporosis (a diminishing of the bones). Optimal calcium nutrition should be promoted for adults, and one of the best sources of calcium is milk or its products. The recommended amount of milk for adults is one pint per day.

An excessive intake of calcium will not cause calcium deposits in the joints, nor will it have any effect on diseases which affect the joints, such as arthritis, gout, and associated conditions. The protective mechanisms in the body regulate the absorption and output of calcium so that the body retains only sufficient to meet its needs.

A condition known as hypercalcemia, characterized by an excess of calcium in the blood, sometimes does develop in infants and young children when an excess of vitamin D is present in the diet. Although vitamin D aids in calcium absorption in the body, it is now believed that excessive amounts of vitamin D can cause an excessive absorption of calcium.

This condition can be reversed by decreasing dietary amounts of vitamin D. Hypercalcemia is also found in patients being treated for peptic ulcers with both excessive alkali therapy and excessive milk intake; however, it does not occur in cases where alkali therapy is not used, even if large amounts of milk are consumed.

Aside from these two conditions, evidence does not support the theory that excessive amounts of calcium are detrimental to the health of an average individual.

Water

What is the minimum requirement for water for an adult?

The minimum adult requirement under the most favorable conditions is about one quart of liquid water per day. This is a true minimum and does not provide a margin of safety. A practical minimum would be two quarts of water per day.

Thirst is a fair “rule-of-thumb” indicator of water need. The thirst signal in infants, however, is not a reliable indicator during illness or once dehydration is established.

Special care must be taken at these times to assure adequate water intake. Attention to adequate water intake for infants and children during hot weather is also necessary.

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