Vitamin D in Food: A Practical Guide
What are the benefits of Vitamin D in your body?
Vitamin D is an essential fat-soluble micronutrient that acts as a hormone in your body to support many vital functions and processes.
Low vitamin D intake is considered a major public health concern, with 13% of the world’s population thought to be deficient. This is particularly a concern if you live further away from tropical areas.
Adequate vitamin D is critical to maintaining strong bones because it is critical to facilitate the absorption of both calcium and phosphorus.
Vitamin D also:
- works with vitamin A to boost your immune system,
- helps prevent asthma and allergies,
- helps prevent type 1 diabetes,
- helps to reduce blood pressure,
- helps to boost testosterone in men,
- avoid excess male hormones in women, and
- reduces the risk of certain cancers in the gut and reproductive organs.
While supplementation may be necessary for some who live in northern areas, adequate sun exposure (UVB radiation) is ideal to maintain healthy vitamin D levels in the blood. Vitamin D levels are also reducing with increasing concern about skin cancer risk hence limiting sun exposure.
However, at the other extreme, excessive vitamin D supplementation can cause excessive absorption of calcium which can end up in places that it shouldn’t (e.g. your arteries which can lead to heart disease).
Vitamin D deficiency symptoms
Lower intakes of vitamin D are associated with:
- stunted growth, and
- softening of the bones and teeth.
How much vitamin D do you need?
The Adequate Intake level of vitamin D (i.e. 10 micrograms per day for adults less than 50 years old) is based on the amount in the diet to maintain healthy blood levels of vitamin D without significant exposure to sunlight.
Practically, however, it is extremely hard to construct a nutrient-dense diet that meets the Adequate Intake of vitamin D from food alone. Vitamin D supplements are typically not as effective as dietary intake or sun exposure, potentially because vitamin D is so tightly related to calcium and phosphorus intake.
The Upper Limit for adults is set at 80 micrograms per day (25 micrograms per day in infants) due to the danger of excess calcium absorption. However, the best way to determine the right vitamin D dose is to monitor your blood tests and titrate your supplementation, food and sun exposure accordingly.
Vitamin D toxicity and overdose
Vitamin D toxicity (hypervitaminosis D) does not result from sun exposure. However, hypercalcemia has been observed in people supplementing high doses of vitamin D (i.e. greater than 50,000 IU per day).
Vitamin D toxicity is unlikely in healthy people with an intake of less than 10,000 IU/day. However, the official Upper Limit for Vitamin D has been set at 4,000 IU per day.
Optimal calcium:phosphorus ratio
However, you can’t just take Vitamin D in isolation and expect the full benefit. In order for vitamin D to do its job properly, you need enough calcium and phosphorus.
Get vitamin D from the sun!
The bottom line is that it’s good to get out and get some sun on your skin on a regular basis (without burning).
You can use the D Minder app to determine how much sun you need based on your location, time of day, amount of clothes you are wearing and skin colour.
Adequate sun exposure is also critical to good sleep and setting your circadian rhythm in an environment where so many of us spend our days and nights under artificial light looking at screens.
Vitamin D2 (ergocalciferol) is made by plants while D3 is the form synthesised by animals. If you’re eating vitamin D containing foods and/or supplementing regularly, then either form is fine. However, if you are not supplementing regularly D3 is better because it will stay in circulation for longer.
Vitamin D works synergistically with vitamins A, B3, K, boron, calcium, copper, magnesium, manganese, phosphorus, sodium and calcium.
Ironically (given that vitamin D is synthesised by the sun) vitamin D in food is unstable in the presence of light.
Vitamin D rich food sources
A nutrient-dense diet will contain a significant amount of vitamin D2 and D3, but not enough to meet your minimum requirement. Foods with more vitamin D are listed below.
- black pepper
Rather than micromanaging your dietary vitamin D, we highly recommend going for a walk with your dog, friend or loved one in the morning or afternoon sun!
The nutrient fingerprint below for foods that contain more vitamin D shows that these foods tend to have a relatively high protein content (e.g. fatty fish).
Nutritious foods and meals to boost your vitamin D intake naturally
If you are experiencing any of the symptoms of low vitamin D or are concerned that your current vitamin D intake is low, then you may be interested in our lists of vitamin D-rich foods and meals.
What you will get:
- Our Nutritional Optimisation Kickstart Guide.
- A list of the most popular 50 foods that contain more vitamin C.
- A list of 100 popular foods that contain vitamin C, and
- An even longer list of 150 common foods that contain more vitamin C to allow you to expand your nutrient-dense repertoire further.