For a rainy day: Why vitamin D is back on the A-list
The demand for vitamin D supplements in SA has soared, and it's got to do with far more than just healthy bones
Boosting vitamin D levels in obese children may promote weight loss and reduce their risk of heart disease as adults, a new study shows.
The “sunshine vitamin” is known for its essential role in bone health and contribution to immunity, but now its potential benefits in boosting weight loss and metabolic health are proving significant.
Professor Evangelia Charmandari, the lead researcher of a European study released on Thursday night, said: “Our findings suggest that simple vitamin D supplementation may reduce the risk of overweight and obese children developing serious heart and metabolic complications in later life.”
Obesity in young South Africans doubled from 2008 to 2015, according to research analysing the body mass index of 28,000 children and adolescents.
Charmandari said: “Although vitamin D deficiency is typically associated with impaired bone health, in recent years it has been increasingly linked with increased body fat accumulation and obesity.”
Vitamin D deficiency is common in the US and testing for deficiency is becoming more frequent in SA, despite the widespread exposure to sunlight. Sunblock seems to block the UV rays, which trigger the production of the vitamin D in the skin.
The demand for vitamin D supplementation in SA has increased over the past 10 years as people have become aware of its value in the body’s absorption of calcium and concerns about deficiency.
Dr Deepa Maharaj, the scientific and technical head of the Self Medication Manufacturers Association of South Africa, said: “There has been an increase in vitamin D supplementation and greater awareness of its role in bone growth and the immune system. People are more aware and self-treating with it.”
The link to obesity is still being investigated and a study among American adults, released in December, found that obese people across age, ethnicity and geography had lower levels of vitamin D.
“This may not always reflect a clinical problem. Obese people need higher loading doses of vitamin D to achieve the same [levels] as normal-weight people,” the paper in the Journal of Endocrinology & Diabetes and Obesity said.
The new research by Charmandari and her team – involving 232 obese children and adolescents over 12 months at the University of Athens Medical School and the Aghia Sophia Children’s Hospital – assessed the impact of giving vitamin D supplementation to 117 of them.
They found the group given the supplements had “significantly lower body mass index, body fat and improved cholesterol levels after 12 months”.
Charmandari recommended that the parents of obese and overweight children consult their doctors about testing vitamin D levels, yet cautioned that the safety and long-term effects of supplementation were not yet known.
This was the first study to look at vitamin D’s impact on children’s weight and the findings were presented at the 57th Annual European Society for Paediatric Endocrinology Meeting.
Next, the team plans to research the effect of vitamin D supplementation on children and adolescents with unhealthy conditions such as high blood pressure, high blood glucose and high cholesterol – all risks for diabetes, stroke and heart disease.
Vitamin D (calciferol) comprises a group of fat-soluble secosterols found naturally only in a few foods, such as fish-liver oils, fatty fish, mushrooms, egg yolks and liver.
The Nutritional Information Centre of the University of Stellenbosch reports the “adequate intake” a day from birth to 50 years old is five micrograms (µg). From 50 to 70 years, this rises to 10 micrograms, and from 70 years and older to 15 micrograms.
The Dietary Guidelines for Americans recommend: “Older adults, people with dark skin and people exposed to insufficient UV B radiation should consume extra vitamin D from vitamin D-fortified foods or supplements.”