With the ongoing seasonal overindulgence between Thanksgiving and Christmas, it won’t be long before our waistline dictates that we shed a few pounds and ease up on the kitchen food raids. Many will enhance their dieting efforts by reaching for over-the-counter potions, supplements, and vitamins to round out their “insufficient” diet.
I’ve illustrated why vitamin C supplements are pointless due, in part, to our nutrient homeostasis, involving a reserve capacity of 2 grams to 5 grams and changes in absorption and excretion rates as needs increase. These three mechanisms play the same role for all nutrients. Reserves are limited for some, but the compensatory mechanisms of increasing absorption rates and reabsorption by the kidneys as needs increase play major roles in nutrient homeostasis on a wide range of nutrient intake for most.
The chronic advertising for the “need for supplements,” creating a significant Illusory Truth Effect [1] for our purported need to meet 100% of the daily vitamin recommendations, has led to more than half of the adult population consuming them. Compounding this with well-recognized and respected groups or academic institutions routinely telling consumers that water-soluble vitamins have no storage capacity and must be consumed daily exacerbates the issue. For example:
“B-complex vitamins and vitamin C are water-soluble vitamins that are not stored in the body and must be consumed each day.” - Colorado State University Extension
“Water-soluble vitamins (vitamin C and the B-complex vitamins, such as vitamin B6, vitamin B12, and folate) must dissolve in water before they can be absorbed by the body, and therefore cannot be stored.”
- Harvard T.H. Chan School of Public Health.
“Water-soluble vitamins are carried to the body's tissues but are not stored in the body.” - National Cancer Institute
These are just a few examples of the widespread misunderstanding you can find online. Now, it would be delusional to think this article will affect the purchasing habits of most consumers. However, for those who want to know the science that most any reasonable dietary habits will sustain the level of vitamins necessary to maintain their respective biological roles for more than a day, consider the text The Vitamins: Fundamental Aspects in Nutrition and Health. A textbook with the “latest coverage of the biochemistry and physiology of vitamins and vitamin-like substances,” written by Geralde Combs, PhD, Professor Emeritus in the Division of Nutritional Sciences at Cornell and member of the National Academy of Science.
“The reserve capacities of the vitamins vary. Each is affected by the history of vitamin intake, the metabolic needs for the vitamin, and the general health status of the individual. Typical reserve capacities of a healthy, adequately nourished human adult to meet normal metabolic needs are as follows:
- 4–10 days—thiamin, biotin, and pantothenic acid
- 2–6 weeks—vitamins D, E, K, and C; riboflavin, niacin, and vitamin B6
- 3–4 months—folate
- 1–2 years—vitamin A
- 3–5 years—vitamin B12”. [emphasis added]
For the average individual, there is a week or more supply of every vitamin, providing significant latitude in maintaining biological functions when dietary habits are not necessarily up to snuff, and with a mindful selection of food, it is easy to meet your nutrient needs without supplements.
Biochemical abnormalities can certainly be displayed before the reserve of a given nutrient is completely exhausted. However, the point is that there is a large buffer zone between the maximum reserve and what must be present for proper cellular function and development. This is a biological necessity for all those population groups who would undergo periods of absence of any given nutrient due to the lack of availability, which historically has been the case for many.
Consider the following analogy. Think of the recommended levels we often hear about, which maximize those nutrient reserves as your car's maximum fuel tank capacity. When the gauge on your dash indicates three-quarters, or one-half, or even a quarter-tank, you never assume the car is not going to run any less efficiently because it won’t. This is also true when you don’t necessarily achieve the so-called recommended daily levels of nutrients. The physiological functions that rely on them will not be compromised when lower storage levels are present.
There are certainly individuals who can benefit from a supplement for specific reasons, but for the vast majority of Americans, they provide no further benefit to your health. An easy but unfortunate example is most Americans' dietary and lifestyle habits, which are abysmal. Yet, supplements have provided no benefit in the prevention of cancer or heart disease.
Of course, this is not a green light to unhealthful dietary habits; these nutrients are associated with lowering heart disease and cancer rates from the hundreds of phytochemicals present in our foods. The complex synergistic effects of all these compounds benefit your health, not the randomized intake of any of the isolated compounds, which advertisers would like you to believe. Adding supplements to your seasonal effort to shed those Holiday pounds will not enhance your results.
[1] Popularized by Nazi “influencer” Joseph Goebbels, the illusory truth effect is the finding that repetition of a message, even a lie, makes it easy to believe – even if you know it is a lie.
