Vitamin D on a plant-based diet

When our exposure to sunlight decreases so does our vitamin D levels. Whilst you can get most of the nutrients you need all year round from plant foods, vitamin D is different.

Vitamin D is a hormone (yes a hormone!) produced from cholesterol when exposed to the sun, which is why it's known as the sunshine vitamin. However, our modern lifestyles mean that many of us struggle to get enough particularly during the winter months which is when we have to turn to fortified foods and supplements.

Functions of Vitamin D:

  • Enables the body to increase calcium absorption when needed

  • Maintains blood levels of calcium and phosphorus

  • Helps regulate blood pressure and insulin production

  • Supports the immune system and brain health

  • Supports cardiovascular health

  • Evidence of its benefits continue to accumulate

Guidelines for getting adequate Vitamin D

Sunlight

  • There are many variables when it comes to sunlight so for now, I will only address Ireland.

  • From late March to late September we may get all the vitamin D we need from sunlight provided we get sun exposure to the face and forearms between 10 am - 3 pm for 15 minutes (light skin) or 30 minutes (dark skin) without sun cream.

  • More time/skin exposure may be required for the elderly and those overweight.

  • To determine if you're getting enough vitamin D during these months arrange to have your vitamin D level tested.

Supplements

  • We have what's called a vitamin D winter here which means from late September to late March we do not get enough exposure to sunlight. During this time and if vitamin D levels are low all year round we rely on fortified foods and a supplement.

  • In Ireland, it's recommended that a minimum of 10ug (400 IU) be taken during the wintertime (800-1000IU/day for most at-risk groups).

  • However, recommended intakes for vitamin D are a subject of debate as many experts suggest 1,000 - 2000IU per day for optimal health. The tolerable upper intake level for vitamin D is 4000IU without medical supervision.

Food sources

  • Few foods, animal or plant, contain vitamin D.

  • Mushrooms exposed to UVB rays contain a compound that can be converted to vitamin D2.

  • There's a growing number of fortified plant-based foods including plant milk, cereals, and juices however if you don't eat enough of these each day, you should take a supplement.

NOTES:

  • For vegans - vitamin D2 is found in plants whilst vitamin D3 has traditionally come from animal sources (such as animal hides and wool). When looking for supplements, ensure they are vegan friendly (a google search will help).

  • Studies comparing D2 & D3 showed both are effective at maintaining serum levels of vitamin D in adults.

Plant-Based DietSerena O'ReillyComment