We’ve all heard that phrase, but does it have any real meaning? According to leading experts in nutrition, medicine and health, the answer is a resounding “yes!” But just how closely related are good health and proper nutrition? Probably a lot closer than you think.
According to A. Marcos, acclaimed research scientist studying eating disorders and elite athletes, “The adequate functioning of [the human immune system] is critically determined by nutrition, and, as a consequence, so is the risk of illness.”
Dr. Marcos’ message is near universal among scientists who study the relationship between nutrition and health. Victoria J. Drake, Ph.D., an LPI Research Associate, reached the same conclusion, stating, “Inadequate intake of macronutrients or selected micronutrients can lead to immune deficiency, impaired hostdefense mechanisms, and therefore, increased susceptibility to infection and disease.” In short, poor nutrition weakens your immune system, leaving you vulnerable to disease. And the correlation is direct and incontrovertible.
In the light of such compelling evidence, dare we ignore our eating habits? Moreover, the nutrition equation is complex and specific, including many sources of proteins, vitamins, minerals and other nutrients. This need for healthful food choice variety cannot be understated because each missing element in your diet may have a very specific negative consequence. In other words, you have to get it all right. Miss one piece of the nutrition puzzle and you’ve got a problem.
As noted in the European Journal of Clinical Nutrition:
“Without adequate nutrition, the immune system is clearly deprived of the components needed to generate an effective immune response. Human malnutrition is usually a complex syndrome of multiple nutrient deficiencies. However, observations in laboratory animals deprived of one dietary element, as well as findings in those rare patients with a single nutrient deficiency, have confirmed the crucial role of several vitamins, minerals and trace elements in the maintenance of immunocompetence. This includes vitamin A, beta-carotene, folic acid, vitamin B6, vitamin B12, vitamin C, vitamin E, riboflavin, iron, zinc, and selenium.. Antioxidant nutrients, for example, play a pivotal role in maintaining the antioxidant/oxidant balance in immune cells and in protecting them from oxidative stress and preserving their adequate function.” (citations omitted, emphasis added)
In short, overall nutrition is critical, but the absence of any single element of nutrition in an otherwise balanced diet can cause serious health problems. Dr. Drake goes into even greater detail in reporting her research on the subject, specifying the numerous consequences of deficiencies in any single nutritional substance, detailing, vitamin by vitamin, what can go wrong. Her analysis is far too complex for this brief overview, but it is worth noting that each deficiency has its own Pandora’s Box of bad outcomes.
For example, take a look at what happens when only Vitamin A is deficient:
“Vitamin A and its metabolites are required for normal functioning of the immune system, the skin and mucosal cells (cells that line the airways, digestive tract, and urinary tract) that function as a barrier and form the body’s first line of defense against infection…therefore, deficiency in this micronutrient results in loss of integrity of the mucosal barriers and increased vulnerability to respiratory and diarrheal diseases and other infections…. Vitamin A supplementation can enhance immunity, decrease susceptibility to infection, and significantly reduce infection-related morbidity and mortality in children.”
In another instance, she outlines the effects of a Vitamin D deficiency:
“The active form of vitamin D…is a potent modulator of the immune system and can profoundly impact immunity. Vitamin D deficiency has been linked to an increased risk of autoimmune diseases (e.g., type 1 diabetes, multiple sclerosis, and rheumatoid arthritis) and certain cancers (colorectal, breast, and prostate).”
And those are just two of many vitamins that Dr. Drake discusses. For example, she notes that “Culture studies have demonstrated a direct antiviral effect of vitamin C…” And “Vitamin E supplementation in the elderly has been shown to improve age-related declines in immune function…Some studies have found that this translates to an increased resistance against infections.” With regard to the antioxidant vitamins, several B vitamins, such as vitamin B6, folate, and vitamin B12, are “important in immunity.”
And, while this is only the most cursory review of Dr. Drake’s detailed and biochemically complex studies, the basic takeaway is breathtakingly simple:
“Poor overall nutrition can lead to nutritional deficiencies that compromise immunity and increase susceptibility to infection and disease. Even subclinical deficiencies in various nutrients may have adverse effects on the immune system…States of malnutrition and infection can aggravate each other and lead to a vicious cycle.”
But Dr. Drake leaves us with good news, so take heart. For she concludes:
“Eating a healthful diet and taking a daily multivitamin-mineral supplement as nutritional insurance will help to maintain optimal immune function…”
In sum, if you find this subject overwhelming and complex, that’s because it is. But the very the simple message could not be clearer: A poor diet is dangerous. A nutritionally varied diet is better, but no guarantee of good health since any single deficiency in an otherwise fine diet may have a very negative effect on your immune system’s ability to keep you healthy. And how many of us are so knowledgeable about the biochemistry of nutrition that we can say with any certainty that we are fully protecting our health? Finally, it is worth mentioning that nutritional deficiencies and their consequences get worse as we age, as noted by almost all experts in the field. So if you are older, it is highly likely that your immune system has been compromised by nutritional deficits.
But there is good news in the conclusions of the studies we have reviewed. The study in the European Journal of Clinical Nutrition concluded that “…the addition of the deficient nutrient back to the diet can restore immune function and resistance to infection.” And Dr. Drake clearly urges us to take a daily multivitamin-mineral supplement as a kind of “nutrition insurance.”