Vitamin D is crucial to our health and wellbeing, but finding the perfect balance of the “sunshine vitamin” can be a little tricky.

Our bodies absorb vitamin D from the sun, but too much sun exposure has also been linked to skin cancer. And, although a healthy diet helps, it still likely won’t provide all your vitamin D requirements. Do we need more vitamin D? How much is too much?

In our conclusion of the “How Much is Too Much?” mini-series, we’re explore the nutrients that we most often lack—and the ones we run the risk of taking too much and overcompensating.

Why is vitamin D important?

Best known for promoting healthy bones and teeth, vitamin D is a fat-soluble substance that functions as both a necessary vitamin and hormone in our bodies. Vitamin D is essential to the health and functioning of your immune system, enhancing the pathogen-fighting powers and decreasing inflammation.

The importance of vitamin D has been long recognized. It is so important to public health that in the 1930s, the United States began fortifying milk with vitamin D to eradicate rickets, a disease that softens and weakens the bones and was once rampant among poor children.

A lack of vitamin D can cause a variety of symptoms, including fatigue, muscle pain or weakness, restless sleep, and even high blood pressure and weight gain. Long-term shortage of vitamin D has been linked to osteoporosis, heart disease, depression, and cancer.

What’s the recommended amount of vitamin D?

The Recommended Dietary Allowance for adults 19 years and older is 600 IU (15 mcg) daily for men and women, and for adults over 70 years it is 800 IU (20 mcg) daily.

Sources of vitamin D

Ultraviolet rays from sunlight on the skin trigger the body’s process of making vitamin D, so fresh air and sunshine is always a good choice. Sunscreen can interfere with absorbing vitamin D, but if you plan to be outside in sunshine for more than an hour, sunscreen with an SPF of 15 is always recommended.

Healthy food choices help. Almost all U.S. milk is fortified with about 3 mcg (120 IU) vitamin D per cup and so are many plant-based alternatives such as soy oat, and almond milk. Read your food labels: vitamin D is added to many breakfast cereals and often to orange juice, yogurt, margarine, and other food products.

A few foods are natural sources of vitamin D:

• Fatty fish (like trout, salmon, tuna, and mackerel)
• Beef liver, egg yolks, and cheese
• Mushrooms

Can we have too much vitamin D?

Yes. While some people might benefit from vitamin D supplements, Harvard Health warns that this is probably a small subset of Americans. Too much vitamin D can even be toxic, leading to calcium buildup or kidney stones.

Finding your balance

Your vitamin D levels can be impacted by:

• where you live, because a lack of sunshine in far-northern locales might interfere your ability to absorb vitamin D from the sun
• diet
• age, because older people frequently have lower levels of vitamin D for a variety of reasons, including less exposure to the outdoors and sunlight
• skin color, because people with darker skin typically have lower levels of vitamin D

Vitamin D is essential to your good health, so check with your doctor if you have reason to be concerned. A blood test can help determine your vitamin D levels.

Meanwhile, take a walk in the sun—it’s one of the best ways to enjoy a healthy dose of the sunshine vitamin.

Thanks for reading!

We hope you’ve enjoyed our How Much is Too Much? mini-series!