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Vitamin D3, officially known as cholecalciferol, is the form of vitamin D that is produced in our skin. UVB radiation from the sun enters the skin, where it converts cholesterol to cholecalciferol (vitamin D3). The kidney and liver then convert vitamin D3 into other substances to provide various functions in the body.
What are the benefits of vitamin D3? It’s helpful in the prevention and/or treatment of these conditions:
Vitamin D: What It Does
One of the primary functions of vitamin D3 is to regulate calcium and phosphorous levels in the blood. Vitamin D3 encourages the body to absorb calcium, which is critical for strong, dense bones. Calcium is also necessary for muscle cells to contract.
There are vitamin D3 receptors in the brain, and low levels of vitamin D have been linked to depression. Vitamin D3 increases the release of serotonin and dopamine, two chemicals that contribute to feeling happier. This is part of the reason why some people feel more depressed in the winter, when there are shorter days with less sunlight.
Researchers found that when subjects with vitamin D deficiency were given vitamin D3, the mitochondria in their muscle cells performed better. The mitochondria is considered the powerhouse of the cell, and produces the energy that is needed for a cell to function (so without good mitochondrial production, muscles don’t perform well). While we still don’t know exactly how vitamin D3 is boosting the mitochondria in muscle cells, this is a promising development toward understanding the role that vitamin D3 plays in preventing fatigue and muscle weakness.
Vitamin D3 Deficiency
Signs of vitamin D3 deficiency include:
- Rickets in children
- Osteomalacia in adults
- Fatigue and muscle weakness
- Depression and anxiety
- Joint pain
- Low blood calcium levels
- Weight gain
Rickets is a condition in which the bones are too soft due to lack of calcium, making them unable to support the body’s weight properly. Children with rickets tend to have bent legs because their growing bones aren’t strong enough to straighten and lengthen normally.
Osteomalacia and osteoporosis occur in older adults. In this case, the bones developed normally originally but now no longer have sufficient calcium to maintain their strength. These fragile bones are more at risk for fractures.
Low levels of vitamin D3 have also been linked to weakened immune systems, which increases the risk of conditions like the flu, asthma, or cancer.
Even if you’re getting enough sunlight and vitamin D3 in your diet, as you age your kidneys will be less efficient at converting it to its usable form. Kidney and liver disease will also hinder conversion. These conditions may require additional supplementation.
Your doctor can run the 25-hydroxyvitamin D blood test to evaluate your vitamin D levels and determine whether or not you have a deficiency.
Vitamin D3 Side Effects
Yup, as well as making sure you are getting enough vitamin D3, you have to watch out for having too much. Too much vitamin D can cause your body to keep too much calcium in the blood. Symptoms can include poor appetite, nausea, and vomiting as well as weakness and kidney problems.
Vitamin D toxicity is usually a result of taking too many vitamin D supplements, and can be avoided by consulting your doctor before taking supplements and having your blood tested regularly to track your vitamin D levels.
Vitamin D3 Supplements and Sources
The easiest way to make sure you are getting enough vitamin D3 is to soak up some sun. Spend 10 to 30 minutes outside, ideally with a fair amount of skin showing (the more skin you have exposed, the more opportunity your body will have to create vitamin D). Just don’t let yourself get a sunburn—you can have too much of a good thing, and sunburns have all kinds of negative consequences. (See also our posts “Skin Cancer Signs? Self-Checks May Help You Avoid Deadly Recurrence” and “Can You Die from Skin Cancer?“)
Getting vitamin D3 from sunlight sounds like a great idea unless you live somewhere with cold, dark winters. To make up for insufficient sunlight, you can sit in front of a light box that produces full-spectrum light, take supplements, or adjust your diet.
Some food sources that have vitamin D3 are beef liver, cheese, egg yolks, and fatty fish such as salmon, herring, catfish, tuna, mackerel, and sardines. Organ meat has higher concentrations of vitamin D than muscle meat. Cod liver oil is another good source if you can stomach the flavor! Beverages like milk and orange juice can be fortified with vitamins by manufacturers, and may contain either vitamin D3 or D2. Foods like cereal and tofu can also be fortified.
For further reading, please see these University Health News posts: