Vitamin D3: Benefits, Dosage, Side Effects

Vitamin D, like other vitamins, is required for health but only in trace amounts. Unlike other vitamins, it is not found naturally in food but can be synthesized in the body. Most people are aware that humans use sunlight to produce vitamin D, also known as the “sunshine vitamin.” However, because modern humans do not get enough sunlight, we end up at the vitamin counter, often perplexed about what to buy.

Our bodies produce vitamin D3, also known as cholecalciferol. You can get D3 or D2 at the supplement counter. Ergocalciferol is vitamin D2, which differs slightly from D3 but behaves similarly in the body. D3 has a slightly higher potency.

The primary distinction between the two supplements is how they are manufactured. D3 is derived from animals, but it can also be synthesized from lichen. D2 is obtained from plants. If you are a vegan or vegetarian, you should read labels carefully.

Although vitamin D is fat-soluble (absorbed along with fat), it is not necessary to take it with oily foods. Food can also provide vitamin D. Many foods in the United States, including soy, almond, and oat milk, are vitamin D fortified. Few foods contain vitamin D in their natural state.

Vitamin D3 Benefits

1.  Bone Health

Vitamin D was discovered by doctors while researching rickets, a bone disorder in children. Rickets is no longer common, but vitamin D is still required for bone health. It is especially important for postmenopausal women who are at risk of osteoporosis

Vitamin D is also used to treat osteomalacia, a more serious bone condition (softening of bones). Calcium absorption is aided by vitamin D. Without vitamin D, the body only utilizes a small portion of the calcium in food.

2.  Anti-Cancer Properties

Vitamin D levels in the blood are linked to lower rates of certain cancers, including colorectal, prostate, and pancreatic. Vitamin D was linked to fewer tumors and slower tumor growth in animal studies. Human clinical trials indicate that vitamin D may not prevent cancer but may slow its progression.

3.  Brain Health

Low vitamin D levels may be a risk factor for Alzheimer’s disease and other forms of dementia. Although animal and cell studies have revealed a link, clinical trial results have been mixed. More research is required.


Experts disagree on how much vitamin D the body requires. The Daily Value (DV) for vitamin D in the United States has been set at 800 International Units (IU).

It is critical not to take too much vitamin D. Vitamin D toxicity is uncommon, but it can be severe, causing symptoms ranging from nausea to bone pain and kidney stones.

A vitamin D deficiency can have serious consequences on the body.

Food Sources

Remember that you have three choices about how to get your vitamin D:

  • Sunlight
  • Your diet
  • Supplements

When your skin is exposed to sunlight, it produces vitamin D3.

UVB radiation from sunlight, in particular, causes the formation of vitamin D3 in the skin from the compound 7-dehydrocholesterol.

If you regularly spend time outside in light clothing and without sunscreen, you may be getting enough vitamin D.

Doctors frequently recommend the supplement due to the dangers of UV rays and the difficulty of obtaining vitamin D through diet alone. Oily fish is the best source of D3, but few people enjoy eating fish on a daily basis.

The following foods are rich in vitamin D, and since they are animal sources, they contain mainly D3:

1.  Rainbow trout, farmed

Just 3 ounces of rainbow trout provides 645 IU for 81% of the DV. It is also rich in heart-healthy omega-3 fatty acids.

2.  Sockeye salmon

Sockeye salmon has slightly less than trout at 570 IU and 71% of the DV. Salmon can contain mercury, but some authorities say the benefits of salmon outweigh the hazards, especially when eaten in moderation.

3.  Sardines

A typical serving of sardines, which is about one can, would provide around 200 IU. Sardines offer other nutrients, such as vitamin B12 and omega-3s.

4.  Egg

One egg contains nearly the same amount of vitamin D as two sardines, with 44 IU and 6% of the DV. Because of the cholesterol content, it is not advisable to eat a lot of eggs.

5.  Beef liver

Some people enjoy eating liver. Some people despise it, but it contains a lot of protein, iron, and vitamin A. It contains a lot of cholesterol, just like eggs. 3 ounces of liver contains 42 IU of vitamin D, or 5% of the daily value.

Side Effects

The main side effects of excessive vitamin D3 levels are related to excessive calcium in the blood.

Some of the main symptoms of hypercalcemia include:

However, not everyone who has hypercalcemia has the same symptoms.

After taking a supplement that was later discovered to contain 78 times more vitamin D than stated on the label, one woman experienced nausea and weight loss.

Importantly, these symptoms occurred in response to extremely high vitamin D3 doses, which resulted in calcium levels greater than 12 mg/dL.

Another case study found that an 18-month-old child who received 50,000 IU of vitamin D3 for three months experienced diarrhea, stomach pain, and other symptoms. When the child stopped taking the supplements, the symptoms went away.

Final Words

Vitamin D3 is critical for your overall health. Even if you eat a healthy diet, you may need to take supplements to maintain optimal blood levels.

It is possible, however, to have too much of a good thing.

Avoid taking excessive amounts of vitamin D3. Taking 4,000 IU or less of vitamin D per day is generally considered safe for people with adequate vitamin D levels.

Vitamin D supplements may be prescribed by healthcare professionals for people who are deficient or insufficient in vitamin D. They will monitor your blood levels to ensure your safety, and once you reach optimal levels, they will reduce your dose or discontinue the supplement.

Unless you are being monitored by a healthcare professional, avoid taking high-dose vitamin D3 supplements.

It’s also worth noting that some cases of vitamin D3 toxicity occurred as a result of people taking incorrectly labeled supplements. If you want to take vitamin D3 supplements, buy them from reputable manufacturers to avoid accidental overdoses caused by incorrect labeling.

If you’ve been taking vitamin D3 supplements and are experiencing any of the symptoms listed in this article, see a doctor right away.

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