VITAMIN D – THE SUNSHINE VITAMIN:
SOME IMPORTANT NEW INFORMATION TO CONSIDER
In reality, Vitamin D is not a ‘Vital Amine’ or “Vitamin” (an essential micro nutrient derived from food). In fact, it is a powerful Steroid Hormone that is mainly derived from the skin’s exposure to sunlight and it circulates widely in the body, affecting other tissues at the cellular level. Vitamin D turns on genes in our DNA that encode for over 1,000 different proteins with many diverse effects. There are vitamin D receptors in over 20 different tissues in the body and they are particularly dense in the brain.
Vitamin D does not occur to any significant extent in any natural foodstuffs. Vitamin D’s main source is the SUN. One Minimal Erythematous Dose (MED) of sunshine will induce approximately 10,000-20,000 IU’s of Vitamin D in your skin. This level peaks in your circulation within about 24 hours and then falls off over the next 3-7 days. It’s the amount of strong, summer, noon-ish sun required to produce a minimal blush of pink in fully exposed, non-sunblocked sun. On a hot summer day in Portland, for un-tanned, white-skinned folks, this is usually about 15-20 minutes. However, for darker skinned individuals, the time needed will often be double and may be up to 6 times longer.
In the Pacific Northwest here, NO AMOUNT of our winter sun will make vitamin D. We are just too far north and the sun is too weak. That is why MANY PEOPLE are Vitamin D deficient or at least “insufficient” during the 4-6 month period when our sun lacks intensity and strength. Moreover, since we have carefully coached folks to avoid the sun and to wear sun-block, many of us do not even make enough vitamin D in the summer months to get us up to optimal, robust levels that will last us through our long “Vitamin D Winter”.
Sunscreen, even one with a low SPF level of only 8, will block 95% of the skin’s ability to make vitamin D. Exposure of just the head, neck and arms is not enough either.
So, how much should you take? This answer isn’t simple because it depends on at least 5 factors:
- Your age. 70% of the ability to make vitamin D in our skin is lost by the time we are 70 years old.
- Your skin pigment or how tan you are. On the one hand, tanning does induce a vitamin D effect, so long as it contains UVB rays; however this is still associated with an increased risk of skin cancer, so should be used minimally and with caution.
- The latitude at which you live. The sun’s effect is dramatically decreased the further away you are from the equator.
- How much out-door work or recreation you do.
- Your diet. If you are an Eskimo and you get 40% of your diet from salmon, then you probably would be vitamin D replete from dietary sources.
How to account for all the variables outlined above? - The full answer is to treat with as much as is necessary to get an adequate serum vit D (OH)-25 level. However, if you remember that 20 minutes in noon-time, summer sun will make 10,000-20,000 IU’s (in a white-skinned person), figure that taking 10,000 IU’s/d would be the equivalent of 15-20 minutes in the sun (but without the risk of skin cancer!). That amount is WAY above the current Recommended Daily Allowance.
The current recommendations were set in 1922 and have not been revised since then. These guidelines were based on the observation that 1 tsp of Cod Liver Oil could prevent Rickets in children, so they started with a recommendation based on the amount of vitamin D present in one tsp of Cod Liver Oil. The current RDA is only 400 IU’s /day but many experts are calling for the government to raise this substantially and apparently, the plan is to raise it to 2,000 IU’s/ day.
When testing vitamin D blood levels however, documented deficiency or insufficiency is another matter. In that case, one has to base recommendations on the treatment of a medical issue, so higher levels of supplementation are both indicated and needed. There’s a difference between preventing overt Rickets in kids and obtaining an optimal level for well being. A robust vitamin D level has been shown to decrease over 20 different cancers – head and neck cancers in animal models were decreased by over 80%! Depression, mood disorders, aches and pains, Fibromyalgia, Chronic Fatigue, Multiple Sclerosis, pregnancy-related Pre-eclampsia – all these medical problems and more, have been shown to improve with vitamin D therapy. There is strong and intriguing evidence that suggests AUTISM may be linked to vitamin D deficiency as well – Wow.
The concerns about vitamin D toxicity are largely unfounded. It is possible to take an amount of vitamin D that would eventually be toxic (since, like vitamins A and E, vitamin D is a fat-soluble vitamin). However, the toxic level is approximately 42 mg per Kg of body weight. Now, 1 mg = 40,000 IU’s, so, for a 60 kg woman (132 pounds), that would be approximately 100,800,000 IU’s in a single dose! There has been no evidence of adverse effects unless Vitamin D has been taken in excess of 40,000 IU’s/day for a prolonged period. In studies that suggested a risk of Kidney Stones from Vitamin D, it was probably the excess Calcium that in fact may have caused this trend. That’s because it turns out that in vitamin D replete folks, lower doses of Calcium are needed: probably only 500 -800mg/d or so – which is good news, since many people (especially elderly) get uncomfortable gas and constipation from Calcium and have had a hard time taking it in the levels that are usually recommended (1,200mg – 1,500mg/d). Vitamin D may actually be more important than Calcium. In the studies that previously showed “no effect” of supplementation with vitamin D, way too low doses (400 IU’s/d) were used and that is probably why no effect was seen.
In Lifeguards, circulating levels of vitamin D are often up around 65 ng/ml by the end of the summer and this probably reflects the levels most of us would have had as the Hunter-Gatherers we were programmed to be. By the way, watch out for confusion between ng/ml and nmoles/liter of vitamin D! These measures are related by a factor of 1 ng/ml = 2.5 nmol/l). Most current experts on vitamin D agree that the lower level of ‘normal’ used by labs is probably also too low: a serum level less than 32 ng/ml is probably ‘Deficient’. If we use this level as the cut-off, up to 80% of the US population may be deficient! From 32-50 ng/ml is probably ‘Insufficient’. A level over 50 is probably desirable. A level up to 100 ng/ml is safe.
Many elderly – MOST – will have vitamin D levels that are WAY too low. Osteoporosis is not the only consequence. Osteomalacia is also very common. Osteomalacia is, in effect, ‘Adult Rickets’. It is characterized by weak, soft, spongy ‘pre-bone’ material that needs vitamin D in order to fully finish mineralizing. These soft bones may also fracture and hurt, just like in Osteoporosis. These two conditions unfortunately cannot be differentiated on a Bone Density scan, because Bone Density scans do not, in fact, measure bone DENSITY: they measure bone MINERALIZATION – so in both conditions they will show up as being “low”, but for different reasons. Folks with Osteomalacia should NOT be on osteoporosis prescriptions! In fact, if they ARE on Osteoporosis medicines and their “bone density” is nevertheless still getting worse, they probably don’t have Osteoporosis – they probably actually have Osteomalacia – and what they really need is large amounts of vitamin D. The D will help them to deposit their circulating Calcium into the soft, spongy ‘pre-bone’ they have that just needs the vitamin D to complete its mineralization. In addition, a low vitamin D level is associated with weaker muscles and poorer balance and in fact the STRONGEST risk factor for hip fractures is FALLING. So, having adequate vitamin D levels helps in several ways to prevent hip and spine fractures. ANYONE YOU KNOW WITH “OSTEOPOROSIS” SHOULD DEFINITEY HAVE THEIR VITAMIN D LEVEL CHECKED. Then they should be treated with enough vitamin D to get their serum level up over 50ng/ml at a minimum.
There is intriguing evidence linking vitamin D to Diabetes. Most Diabetics need to make sure they have a robust circulating serum level of vitamin D (>50ng/ml, maybe higher) because it will decrease the amount of diabetic medicine/insulin they need to maintain normal blood sugar levels. This is because vitamin D appears to act as an anti-inflammatory agent and so it helps the beta cells in the pancreas whose job it is to make insulin but which get inflamed in auto-immune Diabetes.
Vitamin D turns on genes in our DNA that encode for powerful anti-viral, anti-bacterial, anti-inflammation proteins as well. If you are vitamin D Insufficient, you are at RISK for infection; you cannot mount an effective attack against bacteria or viruses. In one study, vitamin D supplementation decreased gum disease – which we know to be a risk factor for pre-term labor. In another study, due to be published next year, 4,000 IU/d of vitamin D eliminated pre-eclampsia in pregnant women. This is related to vitamin D’s effects on the auto-immune system. Some experts think this is the real reason we all get more coughs, colds and influenza in the winter months: because that’s when so many of us are vitamin D deficient and so our immunity is markedly lowered. In one study, a vitamin D serum level above 50 ng/ml ELIMINATED colds completely. It’s also long been known that Tuberculosis patients did better went they were able to move to sunny areas. In addition, markedly lower rates of all-cause cancer mortality have been recognized in the Southern States in the US as far back as the 1940’s. – Probably because of its effects on our immune system.
The risks of heart attack were approximately two and a half times less for men with a vitamin D level above 50 ng/ml. This may also be related to its role as an anti-inflammatory agent. It perhaps explains the widely accepted observation that fish-oil decreases heart disease.
A really informed and interesting expert on vitamin D is Dr John Cannell. He has an organization called The Vitamin D Council. If you go to his website you will find lots of additional information about this fascinating and timely topic, including intriguing evidence that suggests a role of vitamin D deficiency in Autism.
Getting your family and loved ones on an adequate amount of vitamin D may be the most important thing you can do for the health and well being of people you care about.
