Many of my patients know the importance of getting enough calcium to reduce the risk of osteoporosis. They may not know the importance of vitamin D, a nutrient that almost 1 in 4 people fall short on.
In my practice as an OB-GYN, I tell my patients that getting enough vitamin D is crucial for good health. It's essential for building and maintaining healthy bones. It also supports healthy muscle function, helps nerves send messages between your brain and the rest of your body, and keeps your immune system strong to fight illness-causing germs.
If you're unsure how much vitamin D you need or where you should be getting it, read on. Here are the top 6 things I share with my patients about vitamin D.
1. Vitamin D matters for women's health
Vitamin D plays a key role in bone health since it helps your body use calcium to maintain a strong, sturdy skeleton. (Without vitamin D, only 10% to 15% of the calcium from food is absorbed.)
That's especially important for women, who are at higher risk for serious bone diseases like osteoporosis. In fact, nearly 1 in 2 women over age 50 will at some point sustain a fracture, which in older age could lead to life-threatening complications.
Women benefit from vitamin D in other ways, too. Research suggests that adequate vitamin D intake might be tied to a reduced risk of serious health conditions, including:
- Breast cancer
- Heart disease
- Type 2 diabetes
- Multiple sclerosis
- Crohn's disease
- Polycystic ovary syndrome (PCOS)
2. Getting the recommended amount is important
Experts recommend that adults under 70 get 15 mcg (600 IU) of vitamin D daily. Age-related changes to the skin mean older adults are less able to make their own vitamin D. After age 70, I tell my patients to aim for 20 mcg (800 IU) per day.
The average woman consumes around 4.2 mcg (168 IU) of daily vitamin D from food. That might sound low, but people typically get most of their vitamin D — around 80% — through sun exposure.
I tell my patients that the best way to know if they’re getting enough vitamin D is through a simple blood test, which shows results in nanomoles (nmol) per liter (L) or nanograms (ng) per milliliter (mL). For most people, the ideal is 50 nmol/L (20 ng/mL) to 125 nmol/L (50 ng/mL). Blood levels below 30 nmol/L (12 ng/mL) might warrant a supplement.
3. Sunshine is a major source
Your body makes vitamin D when your skin is exposed to the sun, though it's hard to say exactly how much. Factors like cloudiness, smog, older age, and darker skin tone can all reduce the amount of D you take in from sunlight.
Most people can get enough of the nutrient by spending 5 to 30 minutes in the sun between 10 a.m. and 4 p.m. at least twice a week if your face, arms, hands, and legs are exposed without sunscreen (which substantially limits the amount of D your skin can get from the sun).
Even when you're wearing sunscreen, you're likely still getting some D from the sun. That's because most of us simply don't put enough sunscreen on to fully block the sun's UV rays that trigger your body to make vitamin D. (The recommended amount is a shot glass worth of sunscreen, slathered on at least 15 minutes before you go outside.)
However, I warn my patients that the risk of skin cancer typically outweighs the benefit of added vitamin D—especially because there are safer ways to increase your intake. In most cases, I recommend increasing vitamin D through foods or supplements instead.
4. The best way to get more is through diet
It's generally a good idea to get your nutrients from food, including vitamin D, since they come packaged with other vitamins, minerals, and fiber. While supplements may help lower your osteoporosis risk, studies haven't shown a clear benefit between vitamin D supplements and a lower risk for other health problems like heart disease, cancer, or type 2 diabetes.
Vitamin D only occurs naturally in a handful of foods. These include:
- Fatty fish, such as salmon, tuna, mackerel, and trout
- Fish liver oils
- Egg yolks
- Cheese
- Beef liver
- Mushrooms
Many packaged foods are fortified with vitamin D. In fact, most of the dietary D we get here in the U.S. comes from fortified foods, such as:
- Cow's milk
- Plant-based milks like soy milk, almond milk, and oat milk
- Breakfast cereals
- Some yogurts
- Some orange juice
And here's a helpful tip: You can boost your absorption of vitamin D from foods by pairing them with a source of healthy fat. Scramble your eggs or sauté your mushrooms in olive oil or add a scoop of peanut butter to a smoothie made with milk or yogurt.
5. Supplements may be right for certain people.
So, where do supplements come in? Your doctor might recommend taking vitamin D pills if your blood levels of vitamin D are low and you're having trouble getting enough vitamin D from food.
While anyone can have low vitamin D, the risk is higher for:
- Older adults
- People with a BMI of 30 or higher
- People who seldom expose their skin to sunshine
- People with dark skin
- People with digestive health conditions, including Crohn's disease, celiac disease, and ulcerative colitis
- People who have had gastric bypass surgery
If you and your doctor decide that a supplement is a good idea, opt for vitamin D3 over vitamin D2 since it raises your blood levels of vitamin D higher and longer than vitamin D2. And again, it's a good idea to take your pill with a meal or snack that contains some fat.
6. It's possible to have too much of a good thing
When it comes to supplements, more vitamin D isn't always better. Very high blood levels of vitamin D can cause nausea, vomiting, muscle weakness, confusion, pain, loss of appetite, dehydration, excessive urination and thirst, and kidney stones. Extremely high levels could lead to kidney failure, irregular heartbeat, or even death.
The bottom line: Vitamin D is important for the health of your bones and the rest of your body. You may be able to get your fill through food and sun exposure, but if your levels are low, your doctor may recommend a supplement.
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