The Health Delusion: How to Achieve Exceptional Health in the 21st Century

CHAPTER 7

‘D’-LIVERED

OVERVIEW

· When it comes to vitamin D deficiency, we’re faced with a big problem. But what’s the answer?

· Why eating more vitamin D rich-foods simply won’t suffice.

· The role of ‘safe’ sun exposure during the summer months to boost your vitamin D levels.

· How to avoid vitamin D ‘starvation’ in winter with an appropriately dosed vitamin D supplement.

· Finally, how much is enough, and can you have too much of a good thing?

We’ve seen that vitamin D is an indispensable nutrient for our health. Its benefits are not confined simply to our bones, but span many aspects of our health, bolstering our ability to stave off a number of chronic illnesses. Low levels of vitamin D are endemic and are among the most pressing public health issues of our times. To us, it’s simply unacceptable to do nothing, so in this chapter we give you the solution and explain how to boost your vitamin D levels into the desirable range for optimal health.

Let the sun shine

By now you’re probably eager to jump aboard the vitamin D wagon. But much of what we’ve mentioned so far is about levels of vitamin D in the blood, measured in seemingly abstract ‘ng/ml’ units rather than how much you actually need to take in order to reap the benefits. So we’re going to make some no-nonsense recommendations to ensure you know exactly how to get the right amount of vitamin D.

It is important to note that our dietary intake of vitamin D is severely limited – even if you eat relatively good sources, such as oily fish, eggs, liver, meat and fortified foods, you’re still going to fall way short. Diet typically provides less than 10% of our vitamin D requirements, with more than 90% coming from exposure to sunshine¹.

Throughout the whole of our evolution, right up to the present day, our primary source of vitamin D has been sunshine – not food. Just four minutes of summer sun exposure to one quarter of the body (arms and legs) in a young white person can produce 1,000IU of vitamin D². In recent decades, the enthusiastic implementation of sun-awareness campaigns, vociferously encouraging us to reduce our sun exposure and to slap on the sunblock, has ensured the contribution made by the sun to our vitamin D status has diminished massively.

Even in countries with warm, sunny climates, such as Saudi Arabia, the United Arab Emirates, Australia and India, one third to one half of children and adults have vitamin D levels below 20ng/ml³.

We’re not saying that sun exposure is always beneficial. We now know that the effects of sun exposure are cumulative, leading to skin damage and ageing over time. Worse still, ultraviolet radiation, the very stuff that stimulates the skin to make vitamin D, has been classified as a class 1 carcinogen⁴ and is linked to over 85% of malignant melanomas⁵.

In 2007, 58,094 people were diagnosed with melanomas of the skin in the USA⁶, so over-exposure to the sun is definitely not recommended.

A study in sun-drenched Australia found that more than 80% of ‘sun-smart’ dermatologists had low vitamin D levels. In fact, their average vitamin D level was lower than that of the elderly patients in a Melbourne Hospital⁷!

Go out in the sun and you risk skin cancer, stay out of the sun and you risk a plethora of other serious maladies, which leaves us with a massive catch-22.

But what if there was a way to reap the benefits, while avoiding the pitfalls? Could we strike a deal with the sun? After all, isn’t this the way intended by nature? As set out in a unified view by the British Association of Dermatologists, Cancer Research UK, Diabetes UK, the Multiple Sclerosis Society, the National Heart Forum, the National Osteoporosis Society and the Primary Care Dermatology Society, total avoidance of the sun is not the aim. On the contrary, it’s fine to go out in the sun in the middle of the day without sunscreen for a few minutes, as this is all the time you need to make appreciable amounts of vitamin D.

As a rule of thumb, you can only make vitamin D in the sunshine if your shadow is shorter than your height.

It’s important to remember that the exact time we can spend out in the sun varies from person to person, and it’s up to us to know our skin and to let common sense prevail. The key is not to get sunburnt – that’s NEVER a good thing. Taking a ‘little-and-often’ approach is the best policy.

Factors Affecting Vitamin D Synthesis

There is another major glitch when it comes to relying on the sun for vitamin D. In order for the skin to start making vitamin D, a UVB wavelength in the range of 290–320nm is required. This means that if you live in more northerly latitudes, you effectively experience a ‘vitamin D winter’, where even on sunny days during the winter months, it won’t be the correct UVB wavelength to make vitamin D. This is found to be the case under clear conditions in places above 51 degrees latitude, such as London⁸. Indeed, there is no UV radiation of the appropriate wavelength for making vitamin D in the UK between the end of October and the end of March⁹.

In areas of high ozone, the effect is evident from latitudes of 40–42 degrees and above⁸, so we’re talking about cities in the USA such as Omaha, Boston, Chicago, New York, and even sun-rich countries such as Spain, France and Italy. If you live in Boston, you will be unable to make vitamin D from November through February¹⁰. At 70 degrees north (Northern Canada, Russia, Norway, Alaska), the vitamin D ‘winter’ period can last as long as seven months⁸.

We strongly caution against using a sunbed, as any benefits are outweighed by the risks of melanoma. An International Agency for Research on Cancer report found that tanning beds increase the risk of skin cancer by 75% for those who use them before the age of 35¹¹.

So, despite ‘safely’ topping up vitamin D throughout the summer, it’s highly unlikely that you’ll be able to sustain your vitamin D at levels we would consider desirable (at least 20ng/ml, and ideally closer to 30ng/ ml) throughout the winter. From summer to the end of winter, vitamin D levels will typically drop by 6–12ng/ml¹² – enough to catapult someone from a sufficient to a deficient state. Which leaves only one option. For most people, a vitamin D supplement is required to get them through the vitamin D winter ‘famine’.

Supplementation: how much do I need?

When it comes to vitamin D levels, we recommend a range of 20–32ng/ml to be maintained all year round. The reason for the lower limit should be blatantly apparent by now; the reason for the upper limit will be explained a bit further on. With ‘smart’ sun exposure we can achieve this range in the summer, but for those of us who experience a ‘vitamin D winter’ the big question is, how much do we need to supplement?

In the UK, 47% of adults don’t even reach levels of 16ng/ml in the winter/spring, and 87% fail to reach the upper desirable level of 32ng/ ml (in Scotland it’s 92%)¹³. Even in summer, when vitamin D levels peak, a whopping 61% of people still fail to reach that upper advantageous target of 32ng/ml¹³.

We’ve already seen that we can’t look to UK health authorities to lead the way. In their view, there’s no need for a recommendation for ‘healthy’ adults, and only 400IU is required for vulnerable groups, which is tantamount to putting a sticking plaster on a broken leg. We prefer to let real science be our guide. A study from Ireland calculated that, in order to be confident that most adults (97.5%) maintain levels above 20ng/ml during winter, a dose of 1,120IU per day is needed¹⁴. The recommendation would be the same in the UK to achieve these levels. The study indicated that, with sufficient sun exposure during the summer, this recommended intake would keep many people near the upper end of the desirable range (20–32ng/ml) all year round. This gives us a recommendation of about 1,100–1,200IU, taken as a daily supplement from the end of October until the end of March. For ethnic minority groups, who have consistent low sun exposure/extensive skin covering with clothes, supplementation can be taken all year round.

You may not find vitamin D supplements sold in doses of 1,100–1,200IU, but a 1,000IU does the job perfectly. Just take one capsule per day, then on one day of each week take two capsules (eight per week in total) and you will be getting an average ideal daily dose of 1,140IU.

Americans tend to fare a bit better than the Brits – on average they hit the lower end of the desirable range of vitamin D levels, at around 20ng/ml. This is a consequence of a more proactive approach from the population. Some 30% of men and 40% of women in the USA already take vitamin D supplements, whereas the corresponding proportions in the UK are a mere 13% and 20% respectively¹³. To make matters worse, unlike in the USA and Canada, milk is not fortified with vitamin D in the UK. Only margarine is fortified, but with very small amounts. This paints a better picture, but vitamin D measurements for the population in the northern US states are made during the summertime¹⁵. By overlooking the effects of the ‘vitamin D winter’, surely this inflates the levels and gives a false impression? The fact remains that many Americans still don’t supplement vitamin D, and milk, despite being fortified, won’t fill the holes that the lack of sunshine creates. Furthermore, the amount of milk people are consuming has steadily declined in recent decades¹⁶, meaning that winter supplementation is also required in the northern US states and Canada.

The Institute of Medicine (IOM) appears to be somewhat miserly in its recommendations, advocating supplementation of 600IU of vitamin D daily, but only for at-risk individuals, with a notable absence of advice to supplement in winter for those who live in the northern states. And is 600IU really enough? The IOM deems 20ng/ml as sufficient, though this really should be the very bottom of the desirable range (20–32ng/ml), with maximum benefits being seen closer to 30ng/ml. A good rule of thumb is that for every 100IU of vitamin D you consume, your vitamin D levels are raised by 0.4–0.8ng/ml¹⁷. These effects are more pronounced if your levels of vitamin D are already low, and less if they are already higher. We could therefore expect the IOM recommendation to increase vitamin D levels by about 4–5ng/ml.

Vitamin D is seized and locked down by fat cells, effectively taking it out of circulation. The fat holds on to it and doesn’t let go, even when it’s needed¹⁸. It’s been found that, for every 10kg rise in body weight, an extra 17% vitamin D is needed¹⁹. With 68% of the US population classed as overweight or obese, this may have important implications²⁰.

In polar contrast we have the recommendations by Osteoporosis Canada for all adults under 50 to take daily supplements of 400–1,000IU (including during the summer), and for the over-50s to take 800–2,000IU daily. Their recommendations are, if anything, a bit over-zealous, and based on the belief that 30ng/ml is the minimum vitamin D level a population should be achieving, whereas we would suggest it should be the upper end of the range.

As the USA typically experiences greater summer sun exposure and a shorter vitamin D winter (being at a lower latitude), an intake of 800–1,000IU is all that’s needed for those living in the states that experience a vitamin D winter (at 41 degrees latitude and above)²¹. This will ensure people are above the 20ng/ml minimum and put many at the upper end of the desirable range.

For Canada, being at higher latitudes, a recommendation of 1,100–1,200IU, as for the UK, is more suitable. Also, unless you are in a high-risk group with little sun exposure, just like the UK guidelines, supplementation is only needed for the winter and early spring months. As we’re about to see, when it comes to vitamin D, it is all about striking the right balance – neither too little nor too much.

Guidelines for Vitamin D Supplementation in Adults

Supplementation of vitamin D is in the form of D3 (cholecalciferol) and obtained predominantly from sheep’s wool and sometimes fish oil. Vegetarians or vegans sometimes prefer to take the D2 (ergocalciferol) form, synthesized from plants.

Vitamin D is fat soluble, and so the efficiency of vitamin D absorption is dependent on the fat content in the gut. Supplements are best taken with a meal containing fat^22,23.

Proceed with caution

Just as it’s important to ask how much is enough vitamin D, so too we should ask, how much is too much? There are many passionate vitamin D advocates out there who recommend that everyone should be taking mega doses, as high as 5,000IU daily. Even some analytical labs, which have to be scientifically meticulous in their operations, are sending back reports to medical practitioners with recommendations that their patients should be in the 40–80ng/ml range. It is claimed that this is all perfectly safe, as there is no data to show harmful effects at these high levels. The trouble is, they look at short-term studies to assess safety (and even a few years is short term when we’re talking about a substance required throughout our entire lives), and define adverse effects as overt toxicity. In their eyes, when it comes to vitamin D, it’s a case of the more the better.

Our take on this is a bit different. It’s important to appreciate that the way vitamin D works in the body is subtler, and the consequences of excessive amounts could be more insidious in the long term than just looking for an obvious toxic effect in the short term.

One of the big mistakes that people make is to simply view vitamin D as a straightforward nutrient, when it should be regarded as a pro-hormone. Indeed, it’s by hormonal actions that vitamin D can influence almost every tissue in the body, and that’s why it’s of such great importance to our health. But like all hormones, it’s best to keep it within a healthy or optimal range. Having too little puts our health in jeopardy, but so does too much.

History tells us that when we discover the benefits of hormones we have a tendency to get a bit over enthusiastic. Just think about HRT (hormone replacement therapy). Initially it was believed that boosting hormone levels was the elixir of life, yet as the side effects emerged, HRT failed to live up to the hype. Sure, women need oestrogen to build up bone and reduce osteoporosis risk, reduce menopausal symptoms, improve mood, cognitive function, skin appearance and cholesterol levels. It took many decades, however, before we realized the darker side of promoting high levels, as they also increased the risk of endometrial and breast cancer, heart attack and stroke.

The same can be said for the male hormone testosterone. We need the right balance for a healthy cardiovascular system, healthy bones, mood, libido, strength, lean tissue gain, and many other reported benefits besides. But if levels are pushed over and above a ‘healthy’ range we find that, over time, it can stimulate unwanted prostate growth, worsen sleep apnoea, cause adverse changes to lipid profiles and increase blood pressure. Likewise, there are a large number of people with low thyroid hormone levels whose health and quality of life are transformed when they are given supplemental hormones. In the opposite camp are those who have levels that are too high, leaving them feeling equally poorly, and who need medication to reduce their levels.

‘D’ zone

Thinking that vitamin D would be any different makes no sense to us. It will be argued that vitamin D is ‘natural’, as it comes from the sun, and that high levels are what nature intended. That argument just doesn’t hold up. First, we know that excess sun exposure massively increases skin cancer risk, so nature is actually forcing us to restrict our exposure. Second, even if we do have a habitually high sun exposure, it doesn’t raise levels to the dizzy heights touted by many vitamin D enthusiasts. In a study of surfers in Honolulu, with heavy sun exposure of nearly 30 hours a week, the average serum vitamin D level was only 31.6ng/ml²⁴. How can this be? It looks like Mother Nature was smart enough to build in a defence mechanism that prevents us from overdosing on vitamin D from sunshine, as any excess simply gets metabolized into non-active forms²⁵ (a defence mechanism not evolved for supplementation!). You can see that it’s a pretty balanced system, designed to maintain a delicate equilibrium, which makes us fundamentally question the wisdom that ‘more is better’.

As the research stacks up, some early warning signs of potential adverse effects from too much vitamin D are slowly emerging. Data from the third NHANES study in the USA suggested that those with vitamin D levels less than 20ng/ml had a 28% higher mortality rate than those with 30ng/ml or above. Although the correlations were only weak, every 4ng/ml rise in vitamin D levels was linked to a 7% reduction in mortality rate²⁶. So, at first glance you’d be forgiven for thinking that 30ng/ml is the minimum you should target, and probably aim to go that bit higher. But if we look at the results in more detail, this is slightly deceptive. As vitamin D levels increased, mortality rates reduced until entering the 24–30ng/ml range and then started to creep back up. So those with levels above 30ng/ml had a 28% lower mortality rate than those with levels below 20ng/ml. However, those with levels of 24–30ng/ml had a 17% lower mortality rate than those with the levels above 30ng/ml. So it would appear that a mid-range level is optimal. Now, we need to point out that these were not very robust findings and on their own contribute only limited evidence, but they do proffer food for thought and contribute to the growing body of evidence that is emerging to caution us about getting over enthusiastic when it comes to supplementation.

Another study of women in the NHANES found that raising vitamin D levels to above 50ng/ml conferred no extra benefit, and there was a strong chance it increased overall mortality to as high, if not even higher, than those who were deficient²⁷. Put simply, what this means is that both a deficiency and an excess of vitamin D are bad for us, so we should be aiming for the ‘zone’ in the middle, where we get all the benefits but none of the risks. This is exactly what was shown in a study looking at vitamin D and prostate cancer risk, which found that having both a low vitamin D status (<8ng/ml) and a high vitamin D status (>32ng/ml) was associated with higher prostate cancer risk²⁸. A vitamin D level of 40ng/ml or above has also been linked with greater risk of pancreatic cancer²⁹. And likewise, associations between higher vitamin D levels and oesophageal cancer have also been noted³⁰.

Undoubtedly, vitamin D is a complex nutrient which has the potential for both benefit and harm. However, this shouldn’t distract us from the fact that vitamin D deficiency is endemic and that our levels are desperately in need of a boost. Rather, we must learn from the past and not be over-exuberant. As early as the 1930s lab research linked high oestrogen levels and HRT to cancer development, and the body of evidence started growing, but this was ignored and the reported benefits jubilantly embraced instead. It took nearly half a century before it was realized that the risks were serious. Learn from these mistakes, make note of the similar early warning signs coming through from research, and recognize that vitamin D needs to be treated with the same respect as all other hormones.

Just underway is the VITAL study, which is investigating the effects of 2,000IU supplementation of vitamin D in the US population (with the population allowed to consume up to another 800IU from other sources). We strongly suspect this will confirm that too much vitamin D may be as harmful as too little. Where this brings people into the optimal range, we predict this will deliver striking benefits, but in those individuals whose levels go too high, we suspect the results will not be so impressive. So, until the results are published, we advise that no one should consume such levels daily unless under the supervision of a clinician who is testing blood vitamin D levels. ‘Balance is the key’ and addressing the issue of vitamin D deficiency may well be one of the greatest steps we can take when it comes to improving the health of hundreds of millions of people worldwide.

THE PARTING SHOT

Whichever way you look at it, there’s a widespread deficiency of vitamin D across the EU and in swathes of North America. The human and financial costs are vast. The benefits of achieving higher levels of vitamin D for bone health are now indisputable, and wider benefits for our health look increasingly likely. The great scandal is the fact that very little is being done about it. For sure, we need more rigorous clinical trials to confirm with certainty the observed health benefits of vitamin D. But, it’s one thing to recommend restoring levels to a balanced range, and another to take a gung-ho approach to over-supplementing. The great thing is that the range proven to bolster bone health is exactly the same as is needed for the host of other associated benefits we’ve described. So, ironclad evidence or not, these are all bonus features of this essential hormone.

A case of our wellbeing crumbling as health authorities fiddle, it’s up to you to take charge, and ensure you’re in ‘D’ health zone.

SUMMARY AND RECOMMENDATIONS

· It’s virtually impossible to obtain optimal intakes of vitamin D from foods sources alone – the sun has always been our primary source.

· Excessive sun exposure, however, and especially getting sunburnt, dramatically increases the risk of skin cancer and should always be avoided.

· Adequate vitamin D can be obtained in the summer months from ‘safe’ sun exposure – ‘little and often’ is best – combined with the use of supplements, especially in the winter months, to meet the body’s vitamin D needs.

· The ‘magic’ level for vitamin D in the body is in the range of 20–32ng/ml. This is where the sum of the benefits has been observed to peak, and going above or below this level is associated with ill effects.

· A daily dose of 800–1,000IU in the USA, and 1,100–1,200IU in the UK and Northern Europe during the winter months is recommended for most people to maintain vitamin D levels in the desirable 20–32ng/ml range.

· You don’t need to supplement in summer if you are getting regular ‘safe’ sun exposure, or in the winter if you live below 41 degrees latitude.

· Daily intakes should not exceed 1,200IU per day unless a clinician is monitoring your levels through blood testing.