ISLAMABAD  – Vitamin D deficiency has been linked to a host of illnesses and conditions, from heart disease and diabetes to certain types of cancer.

Now a small study of three women suggests that vitamin D deficiency and depression may travel together, and that filling up the “vitamin D tank” may help relieve some of the symptoms.

Whether low levels of vitamin D cause depression, worsen it, or are a symptom of the underlying depression is not fully understood. “There is no solid proof that vitamin D deficiency causes depression,” says researcher Sonal Pathak, MD. She is an endocrinologist at Bay Health Endocrinology in Dover, Del. “Large studies are clearly needed.”

Her findings were presented at The Endocrine Society’s 94th Annual Meeting in Houston. Pathak’s study included three women aged 42 to 66 with depression, all of whom were taking antidepressants. The women were also being treated for type 2 diabetes or an underactive thyroid gland.

All three were deficient in vitamin D, with levels that ranged from 8.9 to 14.5 nanograms per milliliter of blood (ng/mL). Levels below 21 ng/mL are considered vitamin D deficient. Normal vitamin D levels are above 30 ng/mL, according to guidelines set by The Endocrine Society.

The women received vitamin D therapy for eight to 12 weeks to replenish their blood levels. After treatment, their levels increased to 32 to 38 ng/mL. The women also reported corresponding improvements in symptoms of depression following vitamin D therapy. One woman’s depression score changed from one indicating severe depression to mild depression. Another woman’s score improved to a level suggesting she had just minimal symptoms of depression.

Vitamin D is called the sunshine vitamin because our bodies produce it when exposed to sunlight. Vitamin D is also added to milk and other foods, and is available in small amounts in fatty fish like tuna, salmon, and mackerel; beef liver, cheese, and egg yolks. It can be hard to get as much as we need from our diets, which is why supplements are often needed.

The Institute of Medicine recently raised the recommended daily intake to 600 IU for people aged 1-70 and to 800 IU for adults older than 70. Other groups set the bar even higher.

Overtime work in pregnancy may affect baby’s size

A new study shows that pregnant women who spend a lot of time on their feet  and work more than 40 hours a week  may give birth to smaller babies.

The study shows that women who spent long periods on their feet during their pregnancy in jobs such as sales, child care, and teaching had babies whose heads were an average of 1 centimetre smaller than average at birth.

Clocking long hours during pregnancy also had an effect on the baby’s birth weight.

About half the women in the study worked between 25 and 39 hours a week. About one in four worked more than 40 hours a week. The women who worked more than 40 hours a week had slightly smaller babies than those who worked less than 25 hours a week. But there were no differences in rates of preterm delivery, low birth weight, or babies being born too small for their gestational age, the study showed.

The differences in head size and weight were apparent from the third trimester onward. Whether or not these differences affect a baby’s long-term development is not known. The findings appear online in Occupational and Environmental Medicine. The study suggests that changes are needed in work patterns for pregnant women.

“We believe that optimising the work environment is important since participation of women in the reproductive age in the workforce continues to increase,” the researchers write. The research team was led by Claudia A. Snijder, MD, of the Erasmus Medical Centre in Rotterdam, the Netherlands.

Close to 40% of women spent a long time on their feet and 45.5% had to walk for long periods as part of their job, according to the study. Just 6% of women engaged in on-the-job heavy lifting. About 4% worked night shifts. “Anecdotally, we have always known that women who work harder have smaller babies,” says Cynthia Gyamfi, MD. She is the director of perinatal clinics and an associate clinical professor of obstetrics and gynaecology at New York-Presbyterian Hospital/Columbia University Medical Centre in New York City.

Certain changes could help level the playing field for working moms and their kids, she says.