Nutrients Do Not Act Alone
The focus is so much on Vitamin D as a key for wellness (especially for immune strength). But we often lose sight of the fact that Individual Nutrients Do Not Act Alone. Simply "loading up" on Vitamin D without regard to its common co-factors can actually cause new deficiencies and imbalances in the body. What about Vitamin A - an often forgotten fat-soluble vitamin.
Vitamin Who? In recent years, we haven’t heard much about Vitamin A in the US. Unfortunately Vitamin A deficiency is internationally profound and widespread. You may have read about efforts to prevent early childhood death from infectious disease in third-world countries (for which Vitamin A has been a tremendous blessing). But otherwise, conventional medicine media has little to say about this critical nutrient. While overt, life-threatening Vitamin A deficiency is rare in our society, most of us are unaware of the impact (and common risk) of having sub optimal
First of all, it’s important to understand that (like Vitamin D), Vitamin A is both a fat-soluble nutrient and a steroid hormone. Thus it is no surprise that Vitamin A plays a wide range of key functions in the body. It is especially critical for the ongoing health of surfaces which line the body which are called epithelial cells (e.g. our skin, eyes, respiratory tract, GI tract, urinary tract). It is also crucial for good vision (hence the old adage of eating carrots for healthy eyes), and insufficiency can lead to impaired vision or night blindness (for older people in particular). Vitamin A supplementation has also been shown to improve eczema, lower the incidence of kidney stones, protect against the formation of stress-related ulcers, alleviate dry skin or brittle nails, and reduce the incidence of ear infections in children.
Shining a light on a a critical function that is often overlooked, however: Vitamin A plays a major role in immune system strength. First, a little physiology… Our immune system functions with a well-tuned symphony of diverse white blood cell types, all with targeted and critical roles. Vitamin A reduces the negative effects of effector T cells and thus helps to control inflammation (specifically inflammatory TH-17 cells). It also increases our T-regulatory cells which help to balance immune response and prevent auto-immune activation. Vitamin A is also required for secretory IgA production – the critical antibodies that help our immune system to identify friend from foe at the interfaces in our body (e.g. where food meets intestinal villi in the intestines). It also helps regulate the very inflammatory cytokine IL-17. Insufficient levels can lead to loss of immune tolerance and increased susceptibility to infections, allergies, and auto-immune illness. Low Vitamin A is often found in diabetics, alcoholics, and those with auto-immune disease such as Crohn’s Disease.
Vitamin D is also critical for immune system regulation, and many people supplement with it in the months when most Americans cannot make any Vitamin D from the sun (in New England, for example, this is from late September through early May). Even during the summer months in southern states, it will surprise you to learn how many of your people have insufficient Vitamin D (ideally 50-70 ng/ml). But here’s something that might really surprise you: Vitamin D and Vitamin A actually bind to the same final cellular receptor in the body. So increased uptake of one (such as Vitamin D in the summer or when you're taking a supplement) can cause a relative deficiency in the other, if your levels aren’t balanced. If you are someone who gets sick often or has trouble shaking a cold or “stomach bug”, consider asking to have both your Vitamin D and Vitamin A levels checked. Both are simple blood tests, and they are readily available from just about any physician. You are encouraged to ask for your specific data results (not just a letter saying your levels are “fine”). You will want to be in the upper half of the reference range for both.
Why are we deficient? Most multivitamins today include only plant-based precursors to Vitamin A, usually beta carotene. We know clinically that, at best, only 40-60% of beta carotene from plant sources is absorbed. Unfortunately, it’s also estimated that as much as 50% of the population is poor at (or incapable of) converting carotenes to true Vitamin A. Research shows there is extreme genetic variability in our conversion capability. This critical conversion happens in the lining of your intestines and is also dependent on several nutrient co-factors, especially zinc and iron. Thus those with anemia or zinc deficiency (common!) may struggle. Vitamin A conversion will also likely be significantly impaired, if there are gastrointestinal issues such as food allergies/sensitivities, parasite infection, bacterial overgrowth (dysbiosis), digestive enzyme deficiency, gallbladder issues, celiac disease, or fat malabsorption. Complicated GI disorders are a focus area, and unfortunately these circumstances are seen every day. In addition, conversion of beta carotene to the active form of Vitamin A is regulated directly by T3 thyroid hormone. We have an epidemic of subclinical hypothyroidism (which is not, by the way, being necessarily treated well with the conventional protocol of synthetic T4-only medications e.g. levothyroxine such as Synthroid). Many people who take T4-only meds are still deficient in T3 (the only accurate way to check this is to assess specifically the “free T3″ levels). Unfortunately people in this situation are likely to struggle with insufficient Vitamin A.
As you can see, Vitamin A sufficiency can be a challenge! Another barrier to Vitamin A sufficiency in our culture is the mainstream health media’s inappropriate fear-mongering about saturated-fat-containing foods. In fact, natural, healthy, nutrient-dense foods such as organic and grass-fed whole eggs, beef, and butter are excellent sources of fully-formed Vitamin A. And yes, we need to eat the egg yolks (that’s where most of the nutrients are!). Vitamin A is also high in oily fish like mackerel. Beyond food, to boost the immune system (especially if you don’t feel the foods above make you feel your best), I recommend 5000 IU daily of fully-formed vitamin A (i.e. one of the retinoids like retinol palmitate vs. just beta-carotene). Be sure to always take it on a full stomach after a fat-containing meal. If you struggle with any of the ailments I’ve mentioned, I want to encourage you to get your levels tested and try a higher dose of 10,000 IU/day (the tolerable upper intake level recommended by the Institute of Medicine) for a few months if your levels are not optimal.
Contrary to popular myth, true Vitamin A toxicity is extremely uncommon and has been found to occur in adults only at intake levels over 50,000 to 100,000 IU/day (pregnant women should not take more than 10,000 IU/day). Isolated “toxicity” incidents may actually be caused by an imbalance of Vitamin A and D that was mentioned earlier, especially given the high incidence of Vitamin D deficiency in most parts of the US. Common early signs of too much Vitamin A include itchy skin, headaches, bone pain, and nausea which resolve quickly after reducing intake. In summary, realize that you do not have to get a cold or an upper respiratory infection every year! To boost your immune system overall, my recommendation for most is a combination of Vitamin D (minimum 2000 IU/day D3 is safe for almost all), Vitamin A from food or supplement, a probiotic, and zinc (20mg/day is safe for all – don’t get the carbonate form) supplementation along with a diet rich in Vitamin C and K in the form of dark leafy green vegetables.
Vitamin A is yet another example of a nutrient that, in our culture, is not often clinically “deficient (and hence would be dismissed by most physicians) but can indeed be commonly “insufficient” (meaning there is room for improvement). The difference between these two terms can make the critical distinction for someone between simply surviving and truly thriving.
Vitamins & Minerals... Oh my!!! More to come. See you in your inbox