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Get excited about nutrition, and learn as you go with these information-packed resources on a wide variety of nutrition-centric topics! Our bistroMD experts review the importance of the macronutrients protein, fat, and carbohydrates, as well as how to make them work most efficiently for you.

Vitamin-D: What You Need to Know

Vitamin-D: What You Need to Know

Vitamin-D is essential for bone health and is especially beneficial for older adults and women going through menopause. But what is it?

Vitamin-D is a fat-soluble vitamin, found in very few foods, and is needed to maintain strong bones. It does so by helping the body absorb calcium, one of our body’s main building blocks, from food and supplements. Vitamin-D can also be produced from within when ultraviolet rays strike the skin and trigger vitamin-D synthesis.

Why is it important?

Vitamin-D is vital to your body’s health for a number of reasons. First, it is important because your muscles need vitamin-D to move, kind of like the tin man needs oil to move his joints in the fan favorite, the Wizard of Oz. Second, nerves need vitamin-D to carry messages between the brain and every single part of your body. Third, vitamin-D is essential to your immune system because it needs vitamin-D to fight off invading bacteria and viruses. Also, together with calcium, vitamin-D also helps protect older adults from osteoporosis. Vitamin-D plays a role in almost every function of your body, which is why vitamin-D is found in numerous cells throughout your body.

Get it from the sun. It’s free.

Did you know that laying out in the sun on those hot, summer days is actually very beneficial to your body? Your body makes vitamin-D when your skin is directly exposed to the sun. It’s simple and easy so most people get their vitamin-D this way. However, this is not an ideal fix. It’s important to limit your exposure to sunlight so you can lower your risk for skin cancer. When you’re out in the sun for more than a few minutes, it’s a good idea to wear protective clothing and apply sunscreen with an SPF of 8 or more. Also, be weary of tanning beds. They do cause skin to make vitamin-D, but they also pose similar risks for developing skin cancer as well.

Now that you know how to expose your skin to vitamin-D, while taking precautions of course, it’s important for you to also know the ineffective ways to produce vitamin-D. Unfortunately, skin exposed to sunshine indoors through a window will not produce vitamin-D. Also, cloudy days, shade and having dark-colored skin also cut down on the amount of vitamin-D your skin will make.

So how much vitamin-D do I need?

The amount of vitamin-D your body needs will depend on your age. Here are the average daily recommended amounts of vitamin-D according to the Food and Nutrition Board:

      - Birth to 12 months old: 400 International Units (IU)

      - Children 1-13 years old: 600 IU

      - Teens 14-18 years old: 600 IU

      - Adults 19-70 years old: 600 IU

      - Adults 71 years and older: 800 IU

      - Pregnant and breastfeeding women: 600 IU

According to this data, babies need the least amount of vitamin-D, while older adults need the most. Everyone else requires the average amount of 600 IU.

How do you know if you’re getting enough for your body?

Because vitamin-D comes from so many different places—the sun, food and supplements—the best way to measure your vitamin-D status is through your blood levels. In general, levels below 30 nanomoles per liter (nmol/L) are too low for bone or overall health and levels above 125 nmol/L are probably too high. Levels of 50 nmol/L or above are sufficient for most people.

So what does this mean?

In general, young people have higher blood levels of vitamin-D than older adults. And males have higher levels than females. By race, non-Hispanic blacks tend to have the lowest levels. In contrast to that, non-Hispanic whites tend to have the highest levels. The majority of Americans have blood levels lower than 75 nmol/L. Older adults, females and non-Hispanic blacks should watch their vitamin-D consumption.

What happens if you don’t get enough vitamin-D?

People do become vitamin-D deficient if they do not consume enough or absorb enough vitamin-D from food; their exposure to sunlight is limited; or their kidneys can’t convert vitamin-D to its active form in the body. In children, a vitamin-D deficiency could cause rickets—where bones become soft and bend. In adults, vitamin-D deficiency leads to osteomalacia, causing bone pain and muscle weakness.

Vitamin-D and women in menopause.

With hot flashes, irritability and the frustration of sudden weight gain during menopause, it’s easy for nutrition to take a back seat. However, when good nutrition practices are ignored, problems can arise.

“Post-menopausal women need at least 1,000 milligrams of calcium per day in order to maintain optimal bone health,” says bistroMD's founding physician, Caroline J. Cederquist, M.D.

However, calcium is not enough. It’s important to have a balance between calcium and vitamin-D.

“Post-menopausal women do need calcium, but they also need to take that in balance with an appropriate amount of vitamin-D, through supplements,” says Dr. Cederquist.

“Vitamin D is critical in moving calcium to your bones and if you are vitamin-D deficient, like most women are, the calcium you take in will actually move into your arteries, instead of into your bones, which can lead to a heart attack. Most women need 600 IU of vitamin D per day,” says Dr. Cederquist.

What foods should you eat to get your daily vitamin-D?

According to the American Academy of Pediatrics (AAP), children older than 12 months should consume three daily servings of vitamin-D fortified milk and milk products. Also, the AAP states that eating dairy foods such as milk, cheese and yogurt during childhood and adolescence will help build strong bones and reduce the risk of fractures and osteoporosis later in life.

Vitamin-D and calcium are closely linked and despite the numerous health benefits of calcium, Americans are not consuming enough. Close to nine-out-of-10 women (88-percent) and six-out-of-10 men (63 percent), ages 19 and up fail to meet daily calcium recommendations. That’s not good because calcium is very essential to your body’s health. If you want more calcium in your diet try consuming dairy foods like milk, cheese and yogurt.

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