Nutrition are processes by which all living things, including human beings, animals, plants and microorganisms, obtain and use substances in their sources of food that are valuable and essential to their health. Nutrition is the end result of ingestion, absorption and metabolism, the utilization of nutrients.
Studying nutrition involves identifying which nutrients create optimal well- being of the organism and which ingested substances may have harmful effects upon one's nutritional status. Scientists and researchers through the ages have isolated the vitamins, minerals and other substances necessary to human life and have approximated the quantities required for well-being, that is, growth, tissue repair and normal functioning, as well as therapy in the event that toxicity or deficiency of a nutrient exists. Essential inorganic nutrients that promote the growth and maintenance of living organisms are boron, calcium, chlorine, chromium, cobalt, copper, fluorine, iodine, iron, magnesium, manganese, molybdenum, nitrogen, phosphorus, potassium, selenium, silicon, sodium, sulfur, vanadium and zinc (1-4).
Essential organic nutrients, the main sources of carbohydrates, proteins and fats that promote energy for living organisms requiring them are amino acids (the precursors of protein), fatty acids, glucose and other simple sugars, purine and pyrimidine and their derivatives (precursors of nucleic acids) and vitamins. Most of the essential organic nutrients for human beings must be obtained from other living organisms such as animals and plants. All the nutrients required for human life work interdependently in order to metabolize and facilitate optimal functioning. For example, the intake of calcium also requires a certain complementary amount of magnesium so the calcium will be absorbed properly. An excess of calcium may be responsible for a magnesium deficiency; in sum, the nutrients must be balanced. As poor nutrition can induce disease, the state of disease can cause malnutrition (5-7).
Medicinal herbs generally refer to plant parts, sometimes ground, extracted, or otherwise prepared, used for health benefits. Nutraceuticals, a more recent and more general term, refer to a group of natural substances that includes certain herbs and such products as cholesterol-lowering margarines and psyllium-fortified products that are used as dietary supplements and regulated as foods (8-10).
Traditional systems of medicine have been used throughout the world for centuries. Certain ancient systems, such as traditional Chinese medicine, Ayurveda (the holistic system of medicine from India), and Tibetan medicine, are still used extensively, particularly in their country of origin. In the United States, interest in the therapies of such systems, particularly for the treatment of chronic illness, is growing.
These therapies, usually referred to as complementary or alternative medicine range from medicinal herbs to acupuncture to massage. Most of them have not been studied scientifically, and nearly all are unregulated (2).
The most commonly used alternative therapy is dietary supplements, which include medicinal herbs and nutraceuticals. Because the use of dietary supplements is widespread, the United States government passed the Dietary Supplement Health Education Act (DSHEA) in 1994. It defines a dietary supplement as any product (besides tobacco) that contains a vitamin, mineral, herb, or amino acid and that is intended as a supplement to the normal diet. The act requires that the label of a dietary supplement identify it as such. The label must state that the claims for the dietary supplement have not been evaluated by the Food and Drug Administration (FDA). The label must also list each ingredient by name, quantity, and total weight and must identify the plant parts from which each ingredient is derived (11).
Most dietary supplements used in alternative medicine are derived from plants; some are derived from animals. Because such dietary supplements are natural, some people assume that they are safe to use. However, a substance is not necessarily safe just because it is natural. For example, many potent poisons, such as hemlock, are derived from plants, and some, such as snake venoms, are derived from animals. Furthermore, almost all substances that affect the body-- whether dietary supplements or drugs approved for medical use by the FDA have both wanted and unwanted effects (side effects) (12).
Since Dietary Supplements are considered food by FDA, they do not require the manufacturer to prove safety or effectiveness. While some supplements may be good for health, others may cause harm. Food supplements are commonly used during stages when during normal and healthy food pattern is not sufficient enough, like pregnancy, age, stress and illness. The FDA defines dietary supplement as a product people use in addition to the foods they eat (5). This would include:
(e.g.: Vitamin B6, Niacin, Vitamin C)
(e.g.: Calcium and Iron)
III. Amino acid
(e.g.: Tyrosine, Creatine, Theanine, S-Adenosyl Methionine, L-tryptophan)
(e.g.: Ginko biloba, Gotu Kola, Astragalus, Bacopa, Cat’s claw, Echinacea, Ginger, Chamomile, Kava Kava, St. John’s Wort, Alfalfa, Tofu, Ma Huang, Ginseng, Milk thistle, Curcuma longa, Allium sativum, Linum usitatissimum, Aloe vera and Oenothera biennis)
V. Other products
(e.g.: Alpha-Lipoic acids, Essential fatty acids and Carnitine)
The word vitamin refers to organic compounds required in minute amounts to catalyze cellular metabolism essential for growth or maintenance of the organism (13). Vitamins are not utilized primarily as a source of energy or as a source of structural tissue components, but rather as catalysts (14). Vitamins are micronutrients that promote physiological processes necessary for continued life of the organism. There are 13 vitamins; only three of these, vitamins D, biotin and pantothenic acid, are manufactured by the body, and even these may not be sufficient for good health (1). Therefore vitamins must be supplied by exogenous, or from outside, sources. Vitamin deficiency results in a well-defined disease that is prevented or cured by replacement of that vitamin. Physical and Metabolic Properties and Food Sources of the Vitamins are listed in Table 1 (6).
Structure of Vitamins:
Water soluble Vitamins: L- ascorbic acid Dehydro-L- ascorbic acid
Vitamin B complex:
Thiamine (Vitamin B1):
Riboflavin (Vitamin B1):
Table 1: Physical and Metabolic Properties and Food Sources of the Vitamins
Nicotinic acid (Vitamin B3):
R= in NAD and R= PO3 H2 in NADP
Pyridoxine (Vitamin B6):
Panthothenic acid (Vitamin B 5):
Fat soluble Vitamins:
Vitamin E (α –tocopherol):
Vitamin A (Retinol):
Vitamin D (Cholecalciferol):
Vitamin K (Phytonadione):
Risk of free Vitamins:
Vitamin B6 Safe Upper Limit (15)
Similar reasoning led to an SUL (Safe Upper Limits) of 10 mg/day for vitamin B6, even though this vitamin has been used with apparent safety, usually in doses of 50 to 200 mg/day, to treat carpal tunnel syndrome, premenstrual syndrome, asthma, and other common problems. The SUL for vitamin B6 was derived from an animal study, in which a dose of 50 mg/kg of body weight/day (equivalent to 3,000 mg/day for a 60-kg person) resulted in neurotoxicity. The EVM (Expert group on Vitamins and Minerals) reduced that dose progressively by invoking three separate “uncertainty factors”:
1) by a factor of 3, to extrapolate from the lowest-observed-adverse-effect-level (LOAEL) to a no-observed- adverse-effect-level (NOAEL)
2) by an additional factor of 10, to account for presumed inter-species differences
3) by a further factor of 10 to account for inter-individual variation in humans.
Thus, the neurotoxic dose in animals was reduced by a factor of 300, to a level that excludes the widely used 50- and 100-mg tablets. The decision to base the SUL for vitamin B6 on animal data (modified by a massive “uncertainty factor”) was arbitrary, considering that toxicology data are available for humans. A sensory neuropathy has been reported in some individuals taking large doses of vitamin B6.
Most people who suffered this adverse effect were taking 2,000 mg/day or more of pyridoxine, although some were taking only 500 mg/day. There is a single case report of a neuropathy occurring in a person taking 200 mg/day of pyridoxine, but the reliability of that case report is unclear. The individual in question was never examined, but was merely interviewed by telephone after responding to a local television report that publicized pyridoxine-induced neuropathy. Because pyridoxine neurotoxicity has been known to the medical profession for 20 years, and because vitamin B6 is being taken by millions of people, it is reasonable to assume that neurotoxicity at doses below 200 mg/day would have been reported by now, if it does occur at those doses. The fact that no such reports have appeared strongly suggests that vitamin B6 does not damage the nervous system when taken at doses below 200 mg/day. As the EVM did with other nutrients for which a LOAEL is known for humans, it could have divided the vitamin B6 LOAEL (200 mg/day) by 3 to obtain an SUL of 66.7 mg/day. Had the committee been allowed to evaluate both the benefits and risks of vitamin B6, it probably would have established the SUL at that level, rather than the 10 mg/day it arrived at through serial decimation of the animal data.
Niacin (nicotinic acid) Guidance Level (15)
Large doses of niacin (such as 3,000 mg/day) can cause hepatotoxicity and other significant side effects. The EVM focused its evaluation, however, on the niacin-induced skin flush, which occurs at much lower doses. The niacin flush is a sensation of warmth on the skin, often associated with itching, burning, or irritation that occurs after the ingestion of niacin and disappears relatively quickly. It appears to be mediated in part by the release of prostaglandins. The niacin flush is not considered a toxic effect and there is no evidence that it causes any harm. People who do not like the flush are free not to take niacin supplements or products that contain niacin. For those who are unaware that niacin causes a flush, an appropriate warning label on the bottle would provide adequate protection. Granting, for the sake of argument, that the niacin flush is an adverse effect from which the public should be protected, the EVM's Guidance Level still is illogical. The committee noted that flushing is consistently observed at a dose 50 mg/day, which it established as the LOAEL. That dose was reduced by an uncertainty factor of 3, in order to extrapolate the LOAEL to a NOAEL. Thus, the Guidance Level was set at 17 mg/day, which approximates the RDA (Recommended Daily Allowances) for the vitamin. The EVM also noted, however, that flushing has been reported at doses as low as 10 mg, so the true LOAEL is 10 mg/day. Applying the same uncertainty factor of 3 to the true LOAEL would have yielded a Guidance Level of a paltry 3.3 mg/day, which probably is not enough to prevent an anorexic person from developing pellagra. As with manganese, the EVM applied its methodology in an arbitrary and inconsistent manner, so as to avoid being faced with an embarrassing result.
Vitamin C Guidance Level (15)
The EVM concluded that vitamin C does not cause significant adverse effects, although gastrointestinal (GI) side effects may Level based on a NOAEL for GI side effects. It is true that taking too much vitamin C, just like eating too many apples, may cause abdominal pain or diarrhea. The dose at which vitamin C causes GI side effects varies widely from person to person but can easily be determined by each individual. Moreover, these side effects can be eliminated by reducing the dose. Most people who take vitamin C supplements know how much they can tolerate; for those who do not, a simple warning on bottles of vitamin C would appear to provide the public all the protection it needs. Considering the many health benefits of vitamin C, attempting to dumb down the dose to a level that will prevent the last stomachache in Europe is not a worthwhile goal. However, as mentioned previously, the EVM was instructed to ignore the benefits of vitamin C.
Granting, for the sake of argument, that there is value in setting a Guidance Level for GI side effects, the EVM did a rather poor job of setting that level. The committee established the LOAEL at 3,000 mg/day, based on a study of a small number of normal volunteers. An uncertainty factor of 3 was used to extrapolate from the LOAEL to a NOAEL, resulting in a Guidance Level of 1,000 mg/day. However, anyone practicing nutritional medicine knows that some patients experience abdominal pain or diarrhea at vitamin C doses of 1,000 mg/day or less, and the EVM did acknowledge that GI side effects have been reported at doses of 1,000 mg. It is disingenuous to set a NOAEL and then to concede that effects do occur at the no-effect level. To be consistent with the methodology it used for other nutrients, the committee should have set the LOAEL at 1,000 mg/day, and reduced it by a factor of 3 to arrive at a NOAEL of 333 mg/day. The EVM was no doubt aware of the credibility problems it would have faced, had it suggested that half the world is currently overdosing on vitamin C. To resolve its dilemma, the committee used a scientifically unjustifiable route to arrive at a seemingly politically expedient outcome.
II. Minerals (1)
Inorganic elements required for a variety of functions including giving structure to the skeleton, muscle contractions, blood formation, the synthesis of protein and the production of energy. Minerals are found in red blood cells and cell membranes. They are components of hormones and enzymes. Major or “macro” minerals include calcium, phosphorous, sodium, potassium and others. Iodine, iron and zinc are among the “trace minerals” found in very minimal quantities. Some minerals found in even more minute concentrations possibly are necessary for health (1). (Table 2)
Table 2: Minerals essential to health
Major or Macro Minerals:
Calcium Magnesium Potassium Sulfur
Chlorine Phosphorus Sodium
Trace or Micro Minerals
Chromium Iodine Selenium
Copper Iron Zinc
Ultratrace Minerals (Probable essential to health)
Arsenic Lead Nickel
Boron Lithium Silicon
Bromine Manganese Cobalt
Molybdenum Fluorine Vanadium
Physiology and Sources of Nutritionally important Minerals are listed in Table 3 (6).
1- Calcium (1, 16 - 19)
Calcium is the most abundant mineral and the fifth most plentiful substance in the body. The average adult contains from 2 to 3 pounds of calcium, of which 99 percent is found in the bones and teeth. The remaining 1 percent is found in the circulatory system and aids in regulating various body functions. The newborn's skeleton contains about 30 grams of calcium, most of which is deposited during the third trimester of pregnancy. Calcium, which is absorbed from the small intestine, requires the presence of vitamin D. Essential for healthy bone composition, calcium, alone cannot increase bone mass after the age of 20. Although calcium supplements probably do little to reduce the incidence of hip fractures in the elderly, there is little downside to supplements. A French study in elderly women given 800 International Units of vitamin D3 and 1.2 grams of calcium daily demonstrated more than a 40-percent reduction in hip fractures. Results have been mixed in studies designed to see if high calcium intake lowers blood pressure. While animal studies seem to indicate that high calcium intake may protect against colon cancer, proof in humans is lacking.
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