I had a friend years ago who swore if he cut back to less than a few grams of vitamin C a day, he’d get sick. I argued that dose was several hundred times the recommended intake, but sure enough, he’d catch a cold every time he stopped taking supplements.
Hidden within the data of most research studies is this hint of individual nutritional variation. Researchers report on averages, but a hard look at the raw data shows people are responding all over the charts to the same dose. For example, chromium picolinate, on average, has little effect on weight loss. Yet, some people respond quickly remarkably to this mineral, while others show no effect at all.
Individual variability was considered when developing the Recommended Dietary Allowances (RDAs). Age, gender, life stage (puberty, menopause, and reproductive status, such as pregnancy and lactation), body size, and lifestyle are the main variances that distinguish one group from another when establishing nutrient needs and the RDAs. An “Estimated Average Requirement” (EAR) is set based on the amount of a nutrient needed by most people to be healthy, then a safety factor is added. Thus, the RDAs are designed to exceed most people’s requirements, and aim to satisfy at least 97.5% of the population. (A percentage that is guesstimate at best.) A “Tolerable Upper Limit” (UL) for safety of a nutrient is even less clear, since even less is known about individual variability in UL than is known about variability in requirements. Seldom are medical conditions, or even the genetic susceptibility to chronic disease, used as criteria for establishing nutrient requirements. And, the concept of nutritional or biochemical individuality is still in the dark ages.
Current discoveries into mapping the human genome might well be the key to unlocking the mystery of nutritional individuality. The three billion nuceotides distributed sequentially among 23 pairs of chromosomes provide a staggering field for nutrient variations. If the metabolic pathway influencing nutritional requirements for each of the 40+ nutrients (not to mention the 1,000s of phytochemicals!) was affected independently on even two sites at a single genetic locus, we could expect that the number of variations in nutritional variability could be in excess of 200 trillion!
Each of us is genetically unique in our nutritional needs. But, while each of us might not fit the “normal range,” we haven’t a clue as to what to do about that. Until human genome sequencing explains this topic, it’s easy for the message to be misused to justify taking megadoses of vitamins, going on low-carb fad diets, injecting growth hormone, or other senseless, and potentially harmful, practices. Yes, you are unique. Just how unique is still a mystery. Photo credit: micadew via CompfightI