Written by Megan N. Freeland, PharmD, RPh |
Reviewed by Katie E. Golden, MD Updated on February 7, 2023
Key takeaways:
- Your body relies on vitamin D to keep your bones, heart and blood vessels, and immune system healthy.
- Most vitamin D comes from the sun. But it’s also found in some foods and can be taken as a supplement.
- Vitamin D deficiency can increase the risk of developing some health conditions or worsen them.
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You know you need vitamin D for strong, healthy bones, but that’s not all it’s good for. Research shows that having too little vitamin D, also known as vitamin D deficiency, is related to a host of conditions — from heart disease to dementia.
How much vitamin D do you need?
The amount of vitamin D you need every day depends on your age and, in some cases, other factors. The chart below details how much daily vitamin D you should be getting based on your age, according to the U.S. Food and Nutrition Board.
| Age range | Recommended daily intake of vitamin D | Maximum recommended daily intake of vitamin D |
|---|---|---|
| 0-12 months | 400 IU | 1000-1500 IU |
| 1-13 years | 600 IU | 2500-3000 IU |
| 14-18 years | 600 IU | 4000 IU |
| 19-70 years | 600 IU | 4000 IU |
| 71+ years | 800 IU | 4000 IU |
| Pregnant and breastfeeding people of any age | 600 IU | Refer to prenatal care provider |
If you live in cooler, grayer areas or if you have a darker skin tone, you might need to take in more vitamin D than someone who lives in a sunnier environment or has lighter skin. That’s because exposure to sunlight is the main way you absorb vitamin D.
What types of conditions and diseases are linked to vitamin D deficiency?
Below, we discuss seven conditions and diseases that have been linked to vitamin D deficiency.
1. Diabetes
If you have a vitamin D deficiency, you’re more likely to develop Type 2 diabetes. A vitamin D deficiency can also make it harder for you to control your blood sugar if you already have diabetes. That’s because vitamin D helps your body make more insulin. And it helps your body use insulin better.
Vitamin D also helps control inflammation in the body. Too much inflammation can lead to higher blood sugar. That may be particularly important for people with diabetes who have foot ulcers. Without enough vitamin D, foot ulcers and other skin wounds heal more slowly.
2. Heart disease
You probably know about common risk factors for heart disease like high blood pressure and high cholesterol. But low levels of vitamin D can also increase your risk of heart disease.
Vitamin D helps your blood vessels relax and widen. Without enough vitamin D, your blood vessels aren’t as stretchy, and inflammation and clotting are more likely to occur. Vitamin D also helps lower your risk of heart disease by lowering your risk of diabetes.
3. Breast, colorectal, and prostate cancer
If you don’t have enough vitamin D circulating throughout your body, you might be more prone to certain cancers, including breast, colorectal, and prostate cancer. Unfortunately, experts don’t yet know exactly how or why vitamin D deficiency might be linked to cancer. But it turns out that most people with these cancers are vitamin D deficient.
4. Dementia
Even though the exact relationship between vitamin D and brain function isn’t known, it’s true that patients with dementia — and specifically Alzheimer’s disease — are more likely to be vitamin D deficient than not. So it’s especially important to get enough vitamin D to support brain function as you get older.
5. Depression
By stimulating the brain to release “happy hormones” like serotonin and dopamine, vitamin D plays an important role in mental health and mood. These hormones are the ones that help you feel a sense of well-being and happiness. This may explain why people who live in colder, grayer climates (and are therefore more likely to be vitamin D deficient) are more likely to develop issues like depression and schizophrenia.
6. Erectile dysfunction
Earlier, we learned that vitamin D can help relax and widen the blood vessels. Having stretchy blood vessels is critical to getting an erection, which requires blood to be able to flow freely into the vessels in the penis. If those vessels are too stiff, you may not be able to get or keep an erection, a condition known as erectile dysfunction.
7. Osteoporosis and bone disorders
Perhaps one of the most well-known consequences of vitamin D deficiency is osteoporosis, a condition that affects adults and causes bones to be weak and brittle due to a lack of calcium. Likewise, a condition known as rickets, which is characterized by weakened bones and stunted growth, affects children who have prolonged low vitamin D levels.
What are common symptoms of vitamin D deficiency?
How do you know if your vitamin D levels are low? Depending on how low your levels are, you might notice one or more of these symptoms:
- Bone or muscle pain
- Slow healing of wounds
- Depressed or irritable mood
- Fatigue and tiredness
- Hair loss
- Delays in growth or development (for children)
- Hard-to-control blood sugar
- Muscle twitches
- Being prone to breaking bones
- Issues with memory or concentration
However, many of these signs could be related to another condition. And many people with low vitamin D levels don’t notice symptoms at all. So it’s a good idea to have regular checkups with your healthcare provider, who can do a blood test to check your vitamin D levels.
How can I get more vitamin D?
Vitamin D mainly comes from sunlight, select foods, and supplements:
- Sunlight: You can get more vitamin D through direct exposure to the sun. Just keep in mind that anything blocking your exposure (like sunscreen, a window, or the melanin present in darker skin tones) will decrease the amount of vitamin D you take in.
- Foods: Most foods are not high in vitamin D, unless they are fortified with it. Most of the U.S. milk supply is fortified with vitamin D, as are orange juice and breakfast cereals. And you may get some vitamin D from fatty fish (like salmon and tuna), mushrooms, and egg yolks.
- Supplements: If you don’t get enough vitamin D from sun and food, supplements are a good option. Vitamin D supplements come in two forms: vitamin D2 and vitamin D3. You can find safe supplements that are verified by the U.S. Pharmacopeia (USP) here. Always tell your doctor and pharmacist about any supplements, including vitamins, you are taking.
The bottom line
Not having enough vitamin D is a common problem. But most people don’t have symptoms or know that their levels are low.
Over time, vitamin D deficiency can increase the risk of some health conditions. And, for people who already have those conditions, it can make treatment more difficult. Your healthcare provider can help you find out how your vitamin D levels are and develop a plan to get them up if needed. This can help lower your risk of disease and improve your physical and mental health in the long run.
References
American Diabetes Association. (n.d.). Low vitamin D may contribute to insulin resistance.
Littlejohns, T. J., et al. (2014). Vitamin D and the risk of dementia and Alzheimer disease. Neurology.
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