Many chronic health problems stem from micronutrient deficiencies arising from intake of poor diet, drugs, inappropriate nutrient supplements, and environmental depletion. These deficiencies often go undetected for decades. The study of micronutrients and the isolation of them is a young one and frankly still very much a work in progress. The early part of the 20th century marked an exciting time in the science of nutrition as vitamins were isolated and identified as necessary growth factors for human metabolism. I can remember my first exam in my doctorate program, the class was The Biology, Chemistry and Physiology of Micronutrients. Wow I was blown away at the intricacies of human nutrition and the many avenues for things to go wrong. And I had been a practicing pediatric and metabolic dietitian/nutritionist for 6 years prior to returning to school. I think I got a 65 or something on that exam, which turned out to be an A. My friend, a student in the architecture program, said how could a 65 be an A? Can you imagine if only 65 percent of my plans were correct? Indeed why we call it the practice of medicine.
The most reported deficient micronutrient is Vitamin D; it is estimated that over 1 billion people world wide may be lacking in this metabolic powerhouse. Although Vitamin D is labeled as a vitamin, it is not a vitamin in the true sense. Vitamins are described as essential, organic, micronutrients supplied in part by the diet and involved in the growth, maintenance and health of the human body. Natural exposure to sunlight is responsible for maintaining adequate Vitamin D nutrition for most of the world’s population; therefore it is fair to say you do not need a dietary source as with all other vitamins. The more we understand about the availability, metabolism, and actions of Vitamin D the more we need to rethink Vitamin D as a steroid hormone rather than a vitamin. Vitamin D looks and acts much like glucocorticoids (cortisol, etc) and sex hormones (estrogen, testosterone, etc.) If it looks like a duck, swims like a duck and quacks like a duck. Isn't IT a duck?
Vitamin D’s most understood job description is to maintain calcium and phosphorus levels in the blood and bones. It gets this job done by increasing the absorption of these minerals in the intestine. The disease Rickets, a childhood disease of osteomalcia, resulting from severe Vitamin D deficiency, has been described in humans since the 2nd century AD. In the 17th century as civilizations became more industrialized more kiddos suffered from Rickets. Yet the kids in rural areas and even poor-rural areas did not suffer the same fate. Sadly the correlation to sunshine exposure or rather the lack of it was not considered as a culprit for the sickly city kids. Think iPads and video games today. It would be much later when sunshine exposure was actually given the credit it deserved in preventing crippling childhood bone disease. In the 18th and 19th centuries reversal of Rickets included treatment with cod liver oil and sunshine, both excellent sources of Vitamin D!
Given its quasi but not formally titled hormone status, we now know that in addition to keeping the bones up to par, Vitamin D plays a major role in: muscle physiology, nutrient absorption, nerve conduction, respiratory and cardiovascular function, immune response, brain development and mental health. Ever get depressed when it is cloudy or rainy? Ever wonder why the flu and cold seasons are not associated with the sunny months?
We can make Vitamin D from cholesterol in our skin when exposed to sunlight or we can get it in our diet. The cool thing is if a person is exposed to too much sunlight, the body will photodegrade excess Vitamin D to avoid toxicity. Not the case with too many supplements! Pigment in skin is a protective mechanism to prevent the body from making to much vitamin D. Ever wonder why lighter skin is found as you go further from the equator? This was nature's way to ensure folks in the Northern hemisphere could get enough Vitamin D. Why do you think Eskimos eat Fatty Fish?
The main dietary sources of Vitamin D include:
- Fatty fish: tuna, mackerel, salmon
- Beef, liver, cheese, and egg yolks
- Milk, cheese, ice cream
Dietary sources are not what they used to be mainly because animals yielding meat and milk are also deficient in Vitamin D since they don’t see the sun much either. So grass fed and free-range sources of milk and meat are best to ensure adequate vitamin D dietary sources.
Dietary sources aside, if the sun is free, readily available and designed to support nutrition and life, why is everyone deficient in Vitamin D? Okay so it is not that easy, you need the sun, but you also need enough fats and oils in your skin to make the stuff. All the crazy lotions and potions we use today often rob our skin of these needed fats so we start out with a deficit. And for some strange reason we are a nation of fat restrictors, more deficiencies. Try making brownies and forget the oil. Oops. Next even if we have enough oil, the Vitamin D we make is not ready to work until it takes a ride on a special protein and travels through the liver and finally the kidney to pass activation phases. So imagine if you have the oil for your brownies but you have no pan and your oven wont heat up. Making vitamin D in today's lifestyle can be a big challenge!
Factors that negatively impact Vitamin D status:
- Insufficient sun exposure
- Use of sunscreen and skin products
- Intestinal disorders: celiac, Crohn’s, diverticulitis, IBD
- Liver and Renal Disease
- Parathyroid disorder
- Reduced availability in dietary sources
- Caffeine consumption
- Drug or supplement depletion
- Pollution, if your shadow is longer than you are tall, you aren't making vitamin D!
- Exclusive breast feeding
- Fat Restriction
Vitamin D deficiency can present with a host of symptoms including fatigue, depression, muscle aches, and frequent infections or colds. However everyone presents with different symptoms and they may be masked by other illnesses or medications.
What to do?
- Check your numbers, have your health care provider measure 25(OH)D
- Work with a Registered Dietitian/Nutritionist to evaluate your diet and lifestyle to ensure optimal levels of sun exposure and dietary intake
- Don’t take a supplement without getting evaluated. Vitamin D has some real toxicity symptoms: Anorexia, Nausea, Vomiting, Constipation, frequent urination, frequent thirst, and kidney stones to name a few. Also megadoses are not associated with increased blood levels. Actually lower doses often result in greater rises of blood plasma levels indicating the body responds better to moderate doses. Scary as I often see folks on 50, 000 IUs!
- Don’t get supplement advice from a store with profit, not your health, in mind!
Get outdoors, get sunshine on your shoulders, make vitamin D!
From Our Pantry to Yours,
Lea & Emily