Sweet potatoes could lower risk of this common cancer

Dermatologists seem to think the only way to protect yourself from skin cancer is to hide from the sun. That’s just unhealthy. And—as I often report—there’s much more to the story.

In fact, a recent study published in the Journal of the American Medical Association found that people with higher vitamin A intake are far less likely to develop a common form of skin cancer.

But before I get into the study’s details, let’s set the record straight about this little-known, “first-in-the-alphabet” micronutrient…

Unfounded fears about too much dietary vitamin A

Mainstream medicine worries a lot about the supposed dangers of getting too much vitamin A. (They have similar worries about getting too much vitamin D.)

But that concern dates back more than a century to a group of Arctic explorers who subsisted on polar bear livers, which—interestingly enough—contain very high levels of vitamin A. In fact, even just one ounce of polar bear liver can be toxic to humans.

The explorers eventually became very sick, with peeling skin from head to toe. They recovered, but the mainstream has harped on incessantly about getting “too much” vitamin A ever since.

But really, unless you’re an Arctic explorer who subsists on polar bear livers, vitamin A in the diet shouldn’t ever be a problem for you. In fact, as some new research shows, getting enough of this nutrient may actually help protect you from skin cancer.

Higher vitamin A intake reduces skin cancer risk

For the new study, researchers analyzed data involving 75,000 women in the long-standing Nurses’ Health Study and 50,000 men in the well-known Health Professionals Follow-up Study. The participants were in their 50s, on average, at the start of the study. And they provided information on their diet and dietary supplement use.

Over the 25-year study, almost 4,000 people were diagnosed with squamous cell skin cancer. This common type of skin cancer affects 11 percent of men and women in the U.S. at one or more points during their lifetimes. It’s much more common than malignant melanoma skin cancer, which accounts for just about 9 percent of all skin cancers. And it’s not nearly as dangerous as malignant melanoma. But it can be unsightly and require surgical excision.

It turns out, people with the highest intakes of vitamin A had 17 percent lower risk of developing squamous cell skin cancer, compared to those with the lowest intake.

Interestingly, it didn’t take much to get placed in the “highest” vitamin A intake group. In fact, those with the highest intake of vitamin A reported eating, on average, the amount of vitamin A in one medium baked sweet potato or two large carrots daily. They also tended to be older and engaged in more physical activity.

So, clearly, as I mentioned earlier, there’s a lot more to the skin cancer epidemic than just sun exposure. In fact, we now know that spending MORE time in the sun and getting MORE vitamin D also protects against skin cancer.

Of course, at this time of the year, the sun isn’t strong enough in most parts of the U.S. to activate your skin’s production of vitamin D. So, it’s especially important to supplement daily with 10,000 IU of vitamin D, which you can find in an easy-to-use liquid form with or without the potent marine carotenoid astaxanthin.

As for vitamin A, all you need to do is follow these two simple guidelines…

 1.) Only get vitamin A from foods
Like calcium and iron, vitamin A should come only from a healthy diet, not from supplements. (There’s one more reason to skip those useless, and often  dangerous, multi-vitamins!)

2.) Get varied sources of vitamin A

Vitamin A comes in two forms:

  • Preformed vitamin A: This active form of vitamin A is found in full-fat dairy (such as butter, cheese, and milk), fish, and meat. It’s fat-soluble, which means it can be stored in the body.
  • Provitamin A carotenoids: Your liver converts provitamin A carotenoids, such as beta-carotene, into the active form of vitamin A in the body. This form of vitamin A is found in plant foods, including broccoli, cantaloupe, carrots, spinach, squash, sweet potatoes, and sweet red peppers. Plus, provitamin A carotenoids are water-soluble, so you can’t “overdose.” Once converted, though, vitamin A becomes a fat-soluble nutrient—which can be stored (primarily in the liver and fat cells) and can theoretically reach high levels in the body. But, as I said, these high levels are unlikely to occur if you’re following a normal, healthy, balanced diet.

So, at your Thanksgiving table next week, make sure to serve plenty of seasonal vitamin A-rich vegetables, such as pumpkin, spinach, squash, and sweet potatoes. And don’t be afraid to cook them and top them with plenty of butter for an additional boost of this healthy nutrient!

For more healthy holiday food ideas, check out the current November issue of my monthly newsletter, Insiders’ Cures. If you’re not yet a subscriber, now’s the perfect time to get started.


“Association of Vitamin A Intake With Cutaneous Squamous Cell Carcinoma Risk in the United States.” JAMA Dermatology, 2019. doi.org/10.1001/jamadermatol.2019.1937