Lack of sunshine and vitamin D increases your risk of overweight, metabolic syndrome, and type 2 diabetes

Women from the age of 50 years and older have an increased risk of blood sugar problems, weight problems, cardiovascular disease, and metabolic syndrome, if they lack vitamin D, according to a new study from Sao Paulo in Brazil. If you want to control your blood sugar levels and lose weight, it is not sufficient to eat less and work out at the gym. You also need sun exposure (without getting burned), because the summer sun is our richest source of vitamin D. You may even want to take a vitamin D supplement during the winter period.

An estimated one billion people around the globe are believed to lack vitamin D, a nutrient that we primarily get from sunlight. Apparently, there is a link between our habit of avoiding the sun or overusing suncream and the prevalence of metabolic syndrome among women from the age of 50 years and older. Metabolic syndrome is a widespread, insidious metabolic disorder characterized by insulin resistance, elevated blood pressure, elevated blood lipid levels, too large waist circumference, and an increased risk of type 2 diabetes.

Most people with insulin resistance do not notice it in the beginning. Insulin resistance is a condition that prevents a sufficient supply of sugar to body’s cells. The carbohydrate in food is not properly metabolized, so people do not feel satiety, and it may easily become a vicious circle, where you feel hungry all the time, while excess (unused) calories are removed from the bloodstream and stored as potentially harmful fat. The fat typically deposits around the vital organs, causing people to develop a potbelly or an apple-shaped figure. At the same time, the risk of metabolic syndrome and eventually type 2 diabetes increases. This increases the risk of cardiovascular disease, infections, poor wound healing, stroke, and premature death.

Vitamin D deficiency is widespread – even in Brazil

The researchers from the University of São Paulo studied 463 women aged 45-75 years and found that 57.8 percent of the women had insufficient levels of vitamin D in their blood (20-29 ng/ml) or were decidedly deficient (less than 20 ng/ml). Only 39.8 percent of the women had adequate levels of vitamin D in their blood (30 ng/ml or higher).

Direct link between vitamin D levels and metabolic syndrome

The women, all of whom were passed their menopause, were studied several times during a two-year period, where blood levels of vitamin D were held up against the prevalence of metabolic syndrome. The scientists referred to the normal parameters for diagnosing metabolic syndrome, which includes a waist circumference larger than 88 centimeters, elevated blood pressure (higher than 130/85), elevated blood sugar levels (preprandial blood glucose levels above 100 mg/dL), and reduced high-density lipoprotein levels (HDL below 50 mg/dL). Metabolic syndrome was diagnosed in those women who matched three or more of these criteria.
The scientists found that the lower the levels of vitamin D, the higher the rate of metabolic syndrome. Based on their findings, they recommended that women, who have passed their menopause, should make sure to get enough vitamin D from sunlight or from supplements. The study is published in Maturitas, the science journal.

How does vitamin D affect blood sugar levels and metabolic syndrome?

Most of the body’s cells have receptors for vitamin D, which is considered as a lipid-soluble hormone. Earlier studies point to several mechanisms that can explain vitamin D’s effect on blood sugar and metabolic syndrome. The Brazilian scientists suggest that vitamin D can increase insulin sensitivity, which is a major factor.
Insulin is a hormone that is produced in the pancreas and serves as a key for “unlocking” cells and allowing glucose (blood sugar) to enter. It turns out that the insulin-producing beta cells of the pancreas have vitamin D receptors, and scientists believe that vitamin D is necessary for enabling the conversion of pro-insulin (a precursor of insulin) to insulin.

The hypothalamus, the part of the brain that controls appetite, has vitamin D receptors

Scientists have even found vitamin D receptors in the hypothalamus, which is a part of the brain with a superior control function for our hormone system and the autonomous nervous system. It is already known that the hypothalamus helps control our appetite and metabolism, and according to the scientist, Stephanie Sisley, both vitamin D and the hypothalamus play important roles in our control of weight and blood sugar levels.

Official recommendations for vitamin D and our actual requirements

The reference intake (RI) levels for vitamin D are not as high as the levels considered by scientists to be adequate. Many experts believe that the actual need for vitamin D lies somewhere in the range from 30 to 100 micrograms daily. One can easily produce that much vitamin D by exposing oneself to sunlight on a hot summer’s day. However, for people with dark, old, and thin skin, it is difficult to synthesize that amount of vitamin D. Overweight people and diabetics also have difficulty with producing and utilizing the vitamin. In any case, it is a good idea to take a supplement during the winter period, as even a balanced diet only provides limited amounts of the nutrient.

References

Eneida Boteon Schmitt et al. Vitamin D deficiency is associated with metabolic syndrome in postmenopausal women. Maturitas 2018
https://www.maturitas.org/article/S0378-5122(17)30628-X/abstract

Vitamin D might be key to syndrome affecting half of women aged 50 or plus: Research with postmenopausal women, found a 57.8 percent rate of metabolic syndrome among women presenting vitamin D insufficiency or deficiency. -- ScienceDaily
https://www.sciencedaily.com/releases/2018/03/180320141323.htm

Sisley SR et al. Hypothalamic Vitamin D Improves Glucose Homeostasis and Reduces Weight. Diabetes 2016
https://www.ncbi.nlm.nih.gov/pubmed/27217488

http://slankeviden.dk/nyheder/diabetes/51-mangel-pa-d-vitamin-i-hjernen-oger-fedmerisiko.html

Iowa State University: New promise for diabetics with vitamin D-deficiency. ScienceDaily. 2016

Pernille Lund. Sådan får du styr på dit blodsukker. Ny Videnskab 2013