Diabetes and heart disease are conditions that seem to like each other’s company, but it’s a deleterious relationship that never ends well if allowed to get out of control. When it comes to chronic and acute health conditions, the best form of treatment is prevention, so it’ll come as no surprise that researchers are looking into ways to reduce the risk of developing these conditions. Nutrition is the main method of prevention, and often the best form of treatment when it comes to diabetes and heart disease. The Mediterranean diet is considered one of the first lines of treatment for the above conditions due to the low saturated fat, sugar and processed food content, combined with the high mono and polyunsaturated fats, fibre and fruit and veg. However, it may just be a coincidence, but the Mediterranean diet is mainly eaten in sunny, warm climates where people have a greater exposure to UV light…and therefore vitamin D, which leads me on nicely to a recent study that appears to have found a link to vitamin D and the prevention of diabetes and heart disease in mice. Interesting stuff I think you’ll agree.
What does the research say…
A recent study performed at the Washington University School of Medicine suggest a strong association between vitamin adequacy and prevention of diabetes and heart disease. The theory that vitamin D may reduce inflammation and the onset of inflammatory diseases isn’t new, several empirical studies have suggested this in the past, but recently scientists appear to be able to engineer mice so that they lack vitamin D receptors on key immune cells known as monocytes and macrophages, researchers were able to find links between vitamin D, immune cells and inflammation in arteries (one of the main consequences of diabetes and heart disease).
What were the main findings?
One of the main findings of the study was how the ‘switching off’ of vitamin D receptors on monocytes and macrophages (white blood cells or immune cells) resulted in increased inflammation in the liver and artery walls. The researchers also established that the inability of immune cells (monocytes and macrophages) to bind with vitamin D lead to an increased number of these immune cells entering the lining of arteries and depositing cholesterol. The rise in cholesterol levels in artery walls is what results in artery plaque, as well as encouraging the secretion of inflammatory chemicals that increase the risk of diabetes and heart disease.
By ‘turning off’ vitamin D receptors, the white blood cells were unable to bind with vitamin D, which in turn led to a rise in inflammation and depositing of cholesterol in the lining of the artery walls. This finding lends itself nicely to the theory that low vitamin D intakes may increase the risk of inflammation, diabetes and heart disease because of a lack of vitamin D binding with the immune cells (monocytes and macrophages). Without vitamin D, monocytes were able to carry more fat which they inevitably carried to the walls of arteries. Interestingly, researchers suggest that monocytes that don’t carry enough vitamin D also engulf cholesterol and carry it around in the blood stream. This leads to high levels of cholesterol in your blood (a known precursor to heart disease, and a secondary risk of diabetes) which is a known pre-cursor to heart disease.
What this means…
These findings are extremely interesting both for the prevention and treatment of chronic conditions. The findings from this study ultimately suggest that when we are deficient in vitamin D, we run a greater risk of not only LDL cholesterol depositing fatty deposits and OLDL (oxidised low density lipoprotein) into the artery walls… but monocytes laden with fat doing it too! The researchers suggest that this could, and it’s a big could, open doors to potential preventative measurements and treatments for diabetes and heart disease. They explain that the problem may actually be reversible, so mice that had monocytes and macrophages with active vitamin D receptors implanted into them, could in fact reduce inflammation, which in turn lowered blood glucose levels as well as increasing insulin sensitivity.
More research will need to be performed to further validate these findings, but it’s interesting, and promising all the same. You may wish to consider a vitamin D supplement if you feel you may be low in vitamin D because your diet is low in oily fish such as salmon, fresh tuna (not canned), sardines or mackerel, eggs, fortified spreads or cereals, and you don't get much sunlight i.e. you're stuck indoors for large amounts of the day etc.
Jisu Oh, Amy E. Riek, Isra Darwech, Katsuhiko Funai, Jiansu Shao, Kathleen Chin, Oscar L. Sierra, Geert Carmeliet, Richard E. Ostlund Jr., Carlos Bernal-Mizrachi. Deletion of Macrophage Vitamin D Receptor Promotes Insulin Resistance and Monocyte Cholesterol Transport to Accelerate Atherosclerosis in Mice. Cell Reports, 2015 DOI: 10.1016/j.celrep.2015.02.043
Science Daily, (2015). Vitamin D prevents diabetes and clogged arteries in mice. Retrieved 25th March, 2015, from http://www.sciencedaily.com/releases/2015/03/150319123634.htm