In an article in the Yorkshire Post (1) the National Institute for Health and Clinical Excellence (NICE) has released guidance which advocates that Vitamin D supplements should be given out free to people who are at risk of a deficiency (2). NICE claims that about 10 million people in England have low Vitamin D status. This means that a person can be at risk of rickets and weak bones. However Professor Hilary Powers of Sheffield University who chairs the Public Health England Vitamin D working group does not agree. She states that NICE has “jumped the gun” in advising on supplement intake. The current position is that those who are over 65 years old should have 400 International Units (IU) per day, while there is no recommendation for those between the ages of 4 but under 65 years. This is because it is assumed that all of these people will obtain sufficient from their food plus exposure to sunshine.
There is no doubt that we do need to pay much more attention to Vitamin D and its role in public health. Unfortunately the article misses a number of very important issues.
First the official position with respect to lack of any specific recommendation for those between 4 and 65 is completely unrealistic. Many people just do not get out in the sunshine or if they do remain covered up. The widespread use of sun blocs, because of concern about the risks of developing skin cancers, means that the action of the sunlight to produce Vitamin D is inhibited. Even if we get enough sunshine here in countries such as the UK, the stores built up during the summer months will be used up quickly so that for several months there will inevitably be a deficiency. The amounts present in foods are simply too low to provide an adequate supply. On top of this, because Vitamin D is only present in fat, the current emphasis on reducing fat makes it even more difficult to achieve an adequate intake from food sources.
What is of even greater significance is that the current recommendation for very young children is based on the prevention of rickets. However we now know Vitamin D is involved in many other functions in addition to its role in bone formation. It has been established that low levels are associated with increased risks of a range of diseases, including cancer, heart disease, diabetes and Multiple Sclerosis (MS).
Results from the Ludwigshafen Risk and Cardiovascular Health (LURIC) study illustrate the importance of the Vitamin D status with respect to general health and life expectancy(3). Between July 1997 and January 2000, 3316 men and women were recruited in Ludwigshafen in south west Germany who had been referred for coronary angiography. Of these 1801 were found to have Metabolic Syndrome (a cluster of conditions including obesity, diabetes, high blood pressure, raised triglycerides and low HDL Cholesterol). In other words they were high risk for heart disease and related problems. Information was collected and collated on the health and lifestyle. The Vitamin D status was determined by the level in the blood. The participants were followed for almost 8 years, during which time there 462 deaths. The results shown in Table 1 are absolutely fascinating. First of all, there is a progressive fall in the death rate as the level of Vitamin D in the blood increases. Those in the group with the highest Vitamin D have a death rate which is only one quarter that of those with the lowest level. Although this does not conclusively demonstrate that the Vitamin D is the cause of the improved chances of survival it is certainly consistent with that explanation. Furthermore this result does lend support to other findings that ensuring a high level of Vitamin D in the blood is a critical factor in maintaining good health. It is interesting to note that those with a high level of Vitamin D are also much more physically active than those with low values. Perhaps those who take exercise by activities such as walking, jogging or gardening spend more time outdoors. As a result they benefit from exposure to sunshine and build up substantial stores of Vitamin D.
TABLE 1 SELECTED CHARACTERISTICS, VITAMIN D STATUS AND DEATH RATES IN THE LURIC STUDY
|Vitamin D content in the blood|
|<25 nmol/L||25-50 nmol/L||50-75 nmol/L||>75 nmol/L|
|Total Cholesterol, mmol/L||4.8||4.9||5.0||5.0|
|C reactive protein, mg/L||70.2||37.7||34.8||28.7|
|Above average physical activity, %||12.8||27.8||37.1||52.9|
|Adjusted death rate Model 1(All causes)||1.00||0.56||0.48||0.18|
|Adjusted death rate Model 2(All causes)||1.00||0.62||0.56||0.25|
|Adjusted death rate Model 3(All causes)||1.00||0.63||0.61||0.25|
|Adjusted death rate Model 1(CVD)||1.00||0.55||0.36||0.25|
|Adjusted death rate Model 1(CVD)||1.00||0.60||0.45||0.34|
|Adjusted death rate Model 1(CVD)||1.00||0.61||0.49||0.36|
Note: The crude death rates have to be adjusted to allow for differences in age and the relative proportions of men and women in each group. The reason for the 3 different values is that the assumptions in each model vary slightly.
Incidentally the values for Total Cholesterol and LDL Cholesterol are virtually identical despite the 4-fold difference in death rate! Another piece of evidence which undermines the cholesterol theory of heart disease.
While these investigations suggest that many people would benefit from supplementation with Vitamin D the only way to confirm that is the case is to conduct an experiment. Joan Lappe and colleagues at Creighton University in Nebraska have done just this (4). A total of 1179 post-menopausal women aged over 55 years were selected for participation in a double-blind randomized trial, which lasted for 4 years. There were 3 different treatments:
- 1500 mg calcium/day
- Calcium plus Vitamin D (1100 International Units (IU)/day)
Almost 87% of the participants completed the study which is an excellent result.
When any cancers diagnosed in the first year were excluded (to eliminate any which might have been initiated before the study commenced) it was found that those who were taking Vitamin D plus calcium had a relative risk of death due to cancer which was 0.23. In other words their risk of cancer was just one quarter that of those taking the placebo. Those taking calcium only had the same risk as those on the placebo. This reduction in the risk of developing cancer is absolutely huge! It is certainly much greater than could be achieved by the use of drugs. It is especially significant that it fits in with and provides support for the epidemiological results. In this investigation it is not possible to be definitive about the role of the calcium as there was no treatment which was confined to Vitamin D on its own. It is also worth noting that some researchers advocate an even higher dose than 1100 IU/day so it is possible that even more favourable results can be achieved.
It really is time that the official bodies caught up with the latest insight and understanding which has been emerging in recent years and recognized the serious limitations in the current recommendations. In the meantime individuals can decide for themselves to take supplements, especially in the wintertime. Any amount per day of up to 4000 IU will certainly not cause any harm. There are different forms of the vitamin and the preferred one for supplementation is D3. It is also important to ensure there is adequate Vitamin K2 in the diet (see 5).
- G N Thomas et al (2012) Diabetes Care 35 (5) pp1158-1164
- J M Lappe et al American Journal of Clinical Nutrition 85 (6) pp 1586-1591