By Dr. Ananda S Prasad
In 1974 the Food and Nutrition Board of the U.S. National Academy of Sciences made a landmark decision, to declare zinc an essential nutrient and establish recommended dietary allowances for humans.
Later, including zinc in total parenteral nutrition fluids was made mandatory, which undoubtedly saved many lives. Dietary zinc deficiency is very prevalent in the developing world (affecting nearly 2 billion people) where mainly cereals are consumed by the population. A meta-analysis of 33 prospective intervention trials of zinc supplementation and its effects on children's growth in many countries showed that zinc supplementation alone had a statistically significant effect on linear growth and body weight gain, indicating that other deficiencies that may have been present were not responsible for growth retardation.
Zinc supplementation has been shown to improve neuropsychological functions in Chinese children with zinc deficiency. It reduces the incidence and duration of acute and chronic diarrhea and acute lower respiratory tract infections in children in developing countries, resulting in decreased mortality. Zinc deficiency in pregnant women causes:
- Abnormal labor
- Retarded fetal growth
- Fetal abnormalities
The immunological effects of zinc deficiency during the early 1960s were not known, although I knew that patients with zinc deficiency in the Middle East died of infection before the age of 25 (personal observation). It has now been shown that in people with zinc deficiency:
- Activity of serum thymulin (a thymus specific hormone involved in T cell function) is decreased
- An imbalance between T helper cell (Th1) and Th2 function develops
- Lytic activity of natural killer cells and the percentage of precursors of cytolytic T cells are decreased
Zinc deficiency has now been recognized to be associated with many diseases--for example:
- Malabsorption syndrome
- Chronic liver disease
- Chronic renal disease
- Sickle cell disease
- Other chronic illnesses
In these conditions, deficiencies of other micronutrients such as vitamins and other trace elements may also be associated. It should be emphasized that nutritional zinc deficiency in the developing countries does not occur in isolation.
Recently the National Institutes of Health's Eye Institute conducted a large double blind clinical trial including 3,640 elderly participants, which showed that antioxidants and zinc supplements delayed progression of age related macular degeneration and reduced the risk of loss of vision. Zinc deficiency is also common in elderly people.
Zinc decreases the copper burden in humans; as such it has been used effectively to treat Wilson's disease. In therapeutic doses, zinc has been shown to be beneficial in the treatment of:
- Hepatic encephalopathy
- Sickle cell disease
- The common cold
More than 300 catalytically active zinc metalloproteins and more than 2,000 zinc dependent transcription factors involved in gene expression of various proteins have been recognized.
The problem has been known for 40 years and a solution is still outstanding. Despite all the evidence, practically no attention has been given by the world's organizations to the problem of zinc deficiency. Growth retardation and increased susceptibility to infectious and cognitive impairment are common in developing countries where nutritional deficiency of zinc is also prevalent.
British Medical Journal February 22, 2003;326:409-410 (Full Text Article)
This is an excellent comprehensive review on zinc from one of the top zinc researchers in the world. While zinc is an essential component of human nutrition and deficiency can result in some devastating symptoms as discussed above, it is important to avoid the traditional paradigm approach to nutrients.
Most physicians, natural medical doctors and patients have a strong tendency to target nutrients for specific diseases. I believe this is an artifact of being so long rooted in the drug-based health care model. Most of you realize that I am a minimalist when it comes to using supplements but still use them quite a bit when indicated.
The key to supplement use is understanding who needs them and when. This usually involves an individual assessment so that the individual with the disease is treated--not the disease. This is an important distinction; if you supplement with nutrients indiscriminately it is clear they can cause quite serious damage. I have seen this happen all too frequently in many well-intentioned professionals and patients.
Fortunately, nutritional typing in conjunction with hair analysis is often helpful in providing this individualized assessment. I hope to share more details on this topic later this year, but in the meantime my good friend and top-notch nutritionist David Vaughan provides the following pearls on zinc:
People who build or move into new homes with copper pipes should supplement with zinc for a year or two. Copper pipes are a huge unmentioned problem with very long lasting and devastating effects. I think research would show a big increase in cancer (especially female hormone related cancers) from copper plumbing. I also believe there is a strong link between the so-called ADHD/ADD epidemic and copper plumbing. Wouldn't proving that mess up the plumbing industry?!