Top 20 Reasons You May Be Low in Vitamin D

If you stay out of the sun, have a lactose intolerance, or if you are vegan, there is a strong chance that you are one of the 60% of adults in this country who has a vitamin D deficiency. Vitamin D, the sunshine vitamin, is naturally produced by the body through sun exposure. It also exists naturally in some foods like eggs, oily fish and mushrooms, and a number of products are fortified with it, including dairy products, cereal and orange juice.

We need vitamin D in order to absorb phosphorus and calcium. In the past, children who did not have enough vitamin D would develop rickets. While this was almost fully eradicated, it is starting to make a comeback. Additionally, adults can also suffer from various bone problems as a result of deficiency. Furthermore, vitamin D is also important for a host of other elements in the body.

20 Reasons Why You May Be Low on Vitamin D

1. You do not eat the recommended levels of vitamin. This is common in vegans and people who are lactose intolerant, because meat and dairy are the primary sources of vitamin D.

2. You have limited sunlight exposure. This could be due to your geographical location, or you could cover up for religious reasons. You may also use sunscreen whenever you go out in the sun. An SPF 8 sunscreen can reduce the body’s ability to absorb vitamin D by 95%. It is also possible that you, like most other people, spend too much time inside, for instance due to your job.

3. You are dark skinned. Melanin, the skin pigment, lowers the skin’s ability to synthesize vitamin D. In fact, vitamin D deficiency is most common in elderly, dark skinned populations.

4. You have a kidney problem that makes it impossible for vitamin D to become active. This is quite common in the elderly, which is why they are at particular risk of developing a deficiency.

5. You have a problem in your digestive tract, which means you cannot absorb the vitamin. There are a number of medical problems that can cause this, including celiac disease, cystic fibrosis and Crohn’s disease.

6. You are obese. Fat cells extract vitamin D from the blood and determine how it is released into circulation. If your BMI is higher than 30, you are far more likely to have a vitamin D deficiency as well.

7. You take steroid medication, particularly prednisone, which can cause problems with the metabolism of vitamin D. If you regularly take steroid medication, it is important that you talk about vitamin D supplementation with your medical professional.

8. You take weight loss drugs, particularly orlistat (Alli and Xenical are two popular brand names). These drugs are believed to lower the amount of vitamin D that can be absorbed. If you have been prescribed these products, you should also discuss how to maintain or increase your levels of vitamin D.

9. You take cholestyramine (brand names include Prevalite, LoCholest and Questran), which is a cholesterol lowering drug. Make sure you speak to your medical professional about vitamin D supplementation.

10. You take seizure medication, including Dilantin, phenytoin or Phenobarbital, which affects the metabolism of vitamin D. It also affects how your body absorbs calcium. Again, speak to your medical professional about this.

11. You take anti-tuberculosis drugs, which affect the body in the same way as the seizure medication. Interestingly, during the time period of ‘consumption’ (tuberculosis), treatment often consisted of having direct exposure to the sun for long periods of time.

12. You live in the northern parts of the world. If you are higher than the 37th parallel, it is more likely that you have a vitamin D deficiency. This is particularly true during the winter months, when the sunlight’s angle is different. Various studies have confirmed that people in these geographical locations are much more likely to suffer from a deficiency. These studies have led to the recommendation that people take supplements if they live in these parts of the world.

13. You are vegan. Most natural sources of vitamin D come from meat products and dairy products. As a result, if you are vegan, you will find it much more difficult to obtain adequate levels. Most likely, your only natural sources will be cereal, mushrooms and orange juice. There are a number of non-dairy fortified products, including almond milk and soy milk, but the levels are much lower.

14. You are older. According to various studies, between 40% and 100% of people over the age of 65 in this country and in Europe have a vitamin D deficiency. This is significant, since vitamin D deficiency is also linked to cognitive decline and dementia. While many elderly people live in warmer climates, particularly Florida, they continue to be at risk of deficiency. This is firstly because they are more likely to use sunscreen and, secondly, are 75% less able to produce vitamin D simply because of their age.

15. You have medical conditions that are known to be linked to vitamin D deficiency. These include heart disease, osteoporosis, diabetes, high blood pressure, osteoarthritis, rheumatoid arthritis, Parkinson’s disease, infertility, periodontal disease, Alzheimer’s disease and psoriasis. The eternal question, however, is whether these medical conditions caused the deficiency, or whether the deficiency caused the condition, or both. Either way, it is always vital to treat an underlying medical condition.

16. You are pregnant or breastfeeding, which means most of your nutrients will go to your baby.

17. You are a young woman or teenager, who is statistically more likely to have a deficiency. It is not clear yet why this is so.

18. You are a child or infant under 5. Although not quite clear yet why this population group is at increased risk, it is believed to be due to diet and poor sun exposure.

19. You are housebound, which means you cannot go out in the sun.

20. You have to cover your body for religious reasons.

Resources and References:

Vitamin D Insufficiency in North America – Vitamin D defiency in North America. (The Journal of Nutrition)
Vitamin D and Living in Northern Latitudes – An Endemic Risk Area for Vitamin D Deficiency – Vitamin D deficiency in Northern latitudes. (Circumpolar Health Journal)
Vitamin D and African Americans – Vitamin D deficiency in African Americans. (The Journal of Nutrition)
Vitamin D and Risk of Cognitive Decline in Elderly Persons – Link between vitamin D and cognitive decline in the elderly. (JAMA Internal Medicine)
Vitamin D Deficiency in Adults – When to Test and How to Treat – Vitamin D deficiency. (
The Beneficial Role of Vitamin D in Obesity: Possible Genetic and Cell Signaling Mechanics – Vitamin D for obesity. (Nutrition Journal)
Decreased Bioavailability of Vitamin D in Obesity – Vitamin D in obesity. (The American Journal of Clinical Nutrition)