The Benefits of Getting Enough Vitamin D3

Why the sunshine vitamin is important

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Vitamin D3, also known as the “sunshine vitamin,” provides benefits throughout your body. As it circulates through your bloodstream, it aids in the absorption of calcium and phosphorus, which helps keep your bones strong. It's involved in a healthy immune system, and it's beneficial to mood, heart health, and even weight loss. You can get vitamin D from food and supplements, and your skin produces D3 when it's exposed to sunlight.

Close up capsules of vitamin D3
Olga Shumitskaya / Getty Images

What It Is

The Vitamin D you get through dietary supplements or fortified foods comes in two forms:

  • Vitamin D2 (ergocalciferol) is found in some plants.
  • Vitamin D3 (cholecalciferol) is found in animals.

The two types are similar but have some important distinctions. Both require chemical processing in the liver and kidneys in order to become active in the body, but different enzymes activate the different forms.

Once it's active, vitamin D binds to several cells in your body to help them regulate how much calcium and phosphate you absorb from food. The process is the same for D2 and D3, but D3 is more efficient at it and lasts longer than D2. Vitamin D3 is also known to increase vitamin D levels overall in the blood more effectively than D2.

This is why vitamin D3 gets more attention and more space on store shelves—you need less of it for the same effect, so it's the more desirable form.

If you use sunscreen consistently, don't have much sun exposure, and/or have darker skin pigmentation, you may not get the recommended amounts of vitamin D. Since few foods contain the nutrient naturally, supplements may be a good option for some.

Sources

If you'd like to increase your vitamin D levels, you can take supplements, get more sunlight, or increase the amount in your diet. It's difficult to get enough D3 through diet alone, especially if you don't eat a diet very rich in the foods below.

 FOOD IU/SERVING % DAILY VALUE*
Beef liver 42 per 3 ounces 5%
Butter 9 per tablespoon 1%
Cereal 80 per serving 10%
Cheese  12 per ounce 2%
Cod liver oil 1,360 per tablespoon 170%
Egg yolks  44 per yolk 6%
Fresh salmon  570 per 3 ounces 71%
Halibut  384 per half fillet 48%
Mackerel  360 per half fillet  45%
Milk (fortified) 120 per cup 15%
Sardines  46 per 2 fish 6%
Trout  645 per 3 ounces 81%
Tuna 40 per 3 ounces 5%
*Based on the U.S. FDA's recommendation of 800 IU per day.

If you're vegetarian, only a few of those choices may be part of your diet. If you're vegan, cereal may be the only one. That can make supplementation more important. However, you also can add sources of D2 to your diet to receive a little more.

FOOD IU/SERVING % DAILY VALUE*
Almond, oat, or soy milk (fortified)  100-144 per 1 cup 13%-18% 
Mushrooms (portabella) 4 per .5 cup 1%
*Based on the U.S. FDA's recommendation of 800 IU per day.

Supplements

Supplements are the easiest way to ensure you're getting enough vitamin D3 every day, and evidence suggests supplements are just as effective as sunlight and food sources.

If you're interested in taking vitamin D3 supplements, talk to your doctor about whether this supplement is likely to benefit you and what dosage is appropriate. Then, it's time to weed through the options and pick a high-quality product.

Supplements aren't regulated by the Food and Drug Administration (FDA), so you need to buy from trusted brands. Look for "USP Verified" on the label—it means the U.S. Pharmacopeial Convention (a nonprofit scientific organization) has verified that:

  • The label is accurate about the ingredients and potencies
  • The product doesn't contain harmful levels of contaminants
  • The product is absorbable by your body within an appropriate amount of time
  • The product was made in accordance with FDA guidelines and procedures

Sunlight

When the ultraviolet B (UVB) rays from the sun hit special vitamin-D receptor cells in your skin, it triggers a chemical reaction that produces vitamin D3. While getting a little sunlight every day can help you maintain your D3, it's not considered the safest or most reliable way to maintain your D3 levels.

First, there's the cancer risk from the sun's rays. Some experts recommend 10 to 15 minutes of unprotected exposure a few times a week in order to maintain vitamin D levels, but the Centers for Disease Control and Prevention and other medical authorities say there's no safe way to get vitamin D from the sun without increasing cancer risk.

The second issue with relying on sunlight for your body's D3 needs is that it's hard to measure. It's easier with foods and easier still with supplements.

Health Benefits

Vitamin D3 offers many health benefits. It is known to help strengthen bones and muscles, boost immunity, increase mood, aid in weight loss, and improve heart function.

Bones

Vitamin D is known to help both the muscles and bones. It enhances the absorption of calcium in the small intestine. If your body doesn't have enough vitamin D to absorb calcium, it'll pull calcium out of your bones. That makes the bones weak and can lead to fractures and osteoporosis.

Research shows that vitamin D can aid in reducing fractures and improve muscle strength. In addition, high levels of dietary vitamin D3 may be suitable for achieving a higher peak bone mass in adulthood and thereby preventing osteoporosis.

Immunity

Research has shown that vitamin D may help protect against acute respiratory infections and pneumonia.

During the COVID-19 pandemic, some preliminary evidence surfaced suggesting vitamin D deficiency may increase the risk of both infection and severe illness. However, more work needs to be done to say for certain what role—if any—this vitamin plays in the fight against the coronavirus behind the pandemic.

Mood

Studies have shown that people with clinical depression often have vitamin D deficiencies. However, it's not clear whether the deficiency contributes to depression or depression changes behavior (e.g., diet, time outside) and therefore causes the deficiency.

As researchers have examined the impact of vitamin D on the brain, they have uncovered possible mechanisms of action that may shine light on how a deficiency could lead to depression. They've also found evidence that raising vitamin D levels helps alleviate symptoms. Larger, well-designed studies still are needed, but thus far the findings are promising for vitamin D as part of a depression treatment regimen.

Heart Health

Studies have found that individuals with obesity and high blood pressure tend to have lower vitamin D levels. Some research suggested that the vitamin can help lower blood pressure. Some studies have shown that people with higher vitamin D levels have a higher risk of stroke and heart attack, but clinical trials haven't shown that vitamin D supplements reduce the risk.

Weight Loss

In one study, postmenopausal women were given vitamin D3 supplements (compared with a placebo) for a weight loss intervention. The outcome showed that the women who had adequate levels of vitamin D3 lost more body fat, saw a greater reduction in waist circumference, and lost more weight.

However, most research has concluded that vitamin D does not promote weight loss.

Suggested Doses

Unless you are in an area that has a forecast of sunny skies more often than not, it is difficult to get the suggested dose of vitamin D3 naturally through food and the sun. The RDA for vitamin D is 600 IU for people up to age 70 and 800 IU for those over 70.

The safe upper limit of daily intake for most age groups is 4,000 IU. A blood test will let you know if you need additional vitamin D3.

Especially if you've been diagnosed with a deficiency or if you're at risk, you may want to track the amount of vitamin D3 you get from both food and supplement sources to ensure you're getting enough.

Vitamin D3 Deficiency

Research shows that over a billion people worldwide have a vitamin D deficiency. Symptoms and associated conditions include:

  • Muscle weakness and aches
  • Weak bones
  • Fatigue
  • Hair loss
  • Depression
  • Hypertension
  • Inflammation
  • Arthritis
  • Eczema

Risks

Vitamin D3 is generally safe at recommended levels. If you take too much vitamin D3, though, it can have toxic effects. It can cause excessive absorption of calcium, which can lead to a condition called hypercalcemia, which may weaken bones, interfere with the function of your brain and heart, and lead to kidney stones.

Some symptoms of vitamin D toxicity include:

  • Nausea
  • Vomiting
  • Muscle weakness
  • Mood changes
  • Pain
  • Confusion
  • Loss of appetite
  • Dehydration
  • Excessive urination
  • Excessive thirst

Extremely high vitamin D3 levels can lead to:

  • Kidney failure
  • Irregular heartbeat
  • Death

Toxicity problems are caused almost exclusively by taking too many vitamin D supplements. It's difficult to take in that much from food, and your skin limits how much vitamin D your body can produce from sunlight.

Get Your Levels Checked

Before you start taking vitamin D3 supplements, ask your doctor for a blood test to check your levels. That way, you know you're taking a dosage that is both adequate and safe for your needs.

A Word From Verywell

Vitamin D3 is an essential nutrient in the human diet. It's critical for the development and normal functioning of many organs in the body. You should try to get your daily recommended intake of vitamin D3. Try to eat foods that have vitamin D3, and take supplements if you can't get enough from diet.

If you are not sure if you have sufficient levels of serum vitamin D, talk to your doctor about getting a blood test and possibly taking a supplement. As with most other vitamins and nutrients, it may be best to get your daily requirements from food sources. If you need additional supplements, contact a healthcare professional.  

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