What to Eat When You're Pregnant and Vegetarian : Other essential vitamins and minerals (part 3) - Vitamin C, Vitamin D

7. Vitamin D

What it’s for: This vitamin helps with absorption of calcium and building strong, healthy bones. It is particularly important during the later stages of pregnancy. If you don’t get enough vitamin D during pregnancy or while breastfeeding, your baby will have low vitamin D and calcium levels. This can lead to the baby developing seizures in the first months of life. It also puts the baby at risk of developing the bone disease rickets, which results in a softening of the bones as they grow and is characterised by bowed legs. Other symptoms of deficiency in babies are poor teeth formation and general ill health. Not getting enough vitamin D during pregnancy could also mean your baby’s bone mass is lower than it should be in childhood, which means an increased risk of osteoporosis in later life. Recent research also suggests that a lack of vitamin D in pregnancy may also increase the risks of the baby developing multiple sclerosis.

Amount needed: Most adults can get enough vitamin D from a healthy diet and normal exposure to the sun. However, over recent years there has been increasing concern over vitamin D deficiency. Ultraviolet B (UVB) radiation converts a vitamin D precursor in the skin to the active form of the vitamin. People with darker skins are at greater risk of deficiency, as they require longer exposure to sunlight to make the same amount of vitamin D. This means women with darker skin are at greater risk of deficiency than those with paler skin. Women who have limited exposure to sunlight are also more likely to be deficient in vitamin D, for example those who remain covered for religious reasons when they go outside, and shift workers. Women who are pregnant or breastfeeding require extra vitamin D and should take a supplement .

During the summer months, about 15 minutes of sunlight on the hands and face every day will supply enough vitamin D. But in winter, people living at latitudes above 52 degrees (in the UK that means north of Birmingham) are thought to receive no light of the appropriate wavelength to make vitamin D in their skin. This means they have to rely on food and supplements to meet their vitamin D needs. Research has shown that lacto-ovo-vegetarians have lower levels of vitamin D in their blood than non-vegetarians, and vegans have lower levels still.

Where it’s found: Very few foods contain vitamin D naturally and most that do are unsuitable for vegans. All margarines in the UK have had vitamin D added to them since 1940, when there were worries over the nation’s poor intake. The regulations don’t apply to other spreads, such as reduced-fat spreads, but most still have added vitamin D anyway. A growing number of other foods also have vitamin D added, including some (but not all) probiotic drinks, breakfast cereals and soya products.

Two different forms of vitamin D are used for fortification: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Vitamin D2 is usually derived from yeast. It is considered acceptable for vegans and it is often added to soya products and milk-alternatives made from soya, oats or hemp. Vitamin D3 is usually derived from sheep’s wool and is not approved by the Vegan Society. However, the Vegetarian Society approves foods with vitamin D3 added if the D3 is extracted from the wool of live sheep and not after slaughter. Vitamin D3 (from live sheep) is used to fortify some breakfast cereals (including some Kellogg’s products) as well as most margarines and spreads. Many fortified foods just list ‘vitamin D’ on the label without specifying whether they use D2 or D3, but D3 from live sheep is quite widely used. If you are a vegan and want to find out, you can contact manufacturers. Some vegans decide that eating foods with D3 added is a compromise they’re willing to make. Vitamin D2 has been shown in some trials to be much less potent than D3, but this may just be when the immediate response in considered. In the longer term, the two may not be quite so different.