Dry skin is one of those problems that isn’t really dangerous so much as intensely annoying. It can get itchy and painful, but mostly it’s just uncomfortable, especially in the winter when environmental problems like central heating can make it worse.
Most advice about dry skin is focused on what you do to your skin, like washing with harsh soap or moisturizing. But did you know that diet can also affect the way your skin keeps itself hydrated?
Here’s a look at some important nutritional factors that can help with the problem of dry skin (or alternately make it worse). This is not about eczema, or psoriasis, or any other actual diseases; it’s just about the garden-variety dry skin that makes drugstores a killing on hand lotion.
To Get the Obvious Out of the Way: Hydration
The very first thing anyone will tell you about diet and dry skin is to make sure your hydration is on point. And because it’s the very first thing anyone will tell you, you probably don’t need to hear much about it, other than the fact that yes, there is actually scientific evidence that this really does work.
Skin gets dried out when there’s a high rate of water loss from the skin (this is called trans-epidermal water loss, if you want to look it up). Quite a few studies show that people with dry skin have a higher level of water loss through the skin. Drinking more water doesn’t just pump more water into the skin; it actually reduces the rate that water is lost. For example, this study found that adding 2 liters of water to the subjects’ daily water intake measurably improved their skin hydration and reduced the rate of water loss.
So yes, it does help, and if you’re not currently drinking more than 2 liters of water per day, that’s an easy piece of low-hanging fruit to pick. But there are plenty of people who do drink that much (or more) and still have dry skin. So what about other issues?
Vitamins, Minerals, and Other Nutrients
Plenty of nutrients are important for skin health in general, and you can read about them here if you’re interested in that. But for dry skin specifically (rather than acne or other issues), here are a few of the biggies:
Vitamin D is important for overall skin health, but it might have specific benefits for dryness on top of everything else. This study found that high levels of Vitamin D were associated with higher levels of skin hydration, while lower levels of Vitamin D were associated with lower levels of hydration. When the researchers took subjects with dry skin and applied Vitamin D directly to their skin, the subjects’ skin improved and stopped being so dry.
The researchers speculated that this might be one reason why people have so many problems with dry skin in the winter. Vitamin D is available from some foods, but mostly it’s produced in the skin when the skin is exposed to sunlight. On top of all the problems with indoor heating, maybe lower levels of Vitamin D (caused by lower sun exposure) contribute to the problem.
Another biggie is everyone’s favorite anti-inflammatory fat. Omega-3 and Omega-6 fats are critical for maintaining the stratum corneum, the outermost layer of the skin. The stratum corneum controls how well-hydrated the skin ultimately is by controlling how much water evaporates out of the skin. Disrupting the stratum corneum can make skin more vulnerable to dryness. So it’s not hard to see how Omega-3 fats might help protect against dry skin by maintaining the health of the stratum corneum.
There haven’t been any human intervention studies yet, but this study found that, in rats, fish oil supplements reduced skin dryness.
This one’s a bit of a black horse. Hyaluronan (or hyaluronic acid; they’re two names for the same thing) is found in skin and joints of vertebrates – that’s any animal with a backbone, including pigs, cows, sheep, chickens, ducks, and you. That means it was a big player in ancestral and traditional diets, when people used to eat all the parts of the animal.
Hyaluronan is a common ingredient in cosmetics and beauty products (and fun trivia fact about that: actually a lot of that hyaluronan comes from chicken combs, so if you use some fancy anti-dryness or anti-aging lotions, you might be rubbing chicken combs on your face). It also works when you eat it. A recent study found that dietary hyaluronan decreased skin dryness after 3-6 weeks of taking a supplement. That was a follow-up to another study from some of the same researchers finding basically the same thing for a 4-week period of supplements.
You could take a supplement like the study subjects, or you could just eat some delicious pork rinds, bone broth made with joints and skin, or other animal sources of hyaluronan.
Dry Skin, Dieting, and More Serious Problems
It’s also worth noting that dry skin is noted in quite a few studies as a side effect of very low-calorie diets. The connection here might be the thyroid. Low-calorie diets suppress thyroid function. Thyroid hormones act directly on the skin to affect moisture content. People with hypothyroid disorders often have rough or dry skin: in this study, 65% of hypothyroid patients had dry skin.
If you have a thyroid disorder, obviously the solution is to see a doctor, but if you’re just eating something ridiculous like 800 calories a day, the solution is to eat! That sounds like a diet nobody would ever go on without trying, but if you’re eating a low-carb, low-fat “Paleo” diet with a lot of skinless chicken breast and canned tuna, it’s actually not that hard.
Dry skin can also be a sign of diabetes (this study found that about 26% of people with diabetes had problems with dry skin).
Most people who have dry skin probably don’t have diabetes or any thyroid issues, but if you have other symptoms of either problem, it might be worth getting checked out.
Summing it Up
Dry skin is a symptom that can mean all kinds of things. It can be a sign of serious diseases, like diabetes or autoimmune hypothyroid disorders. It can also be just a problem of environment: too much exposure to central heating, living in a dry climate, or washing the skin too often.
But there’s also quite a bit of evidence connecting dry skin to various nutritional problems. Omega-3 fats are structurally important for skin health and deficiency there might be causing a problem. Another big player is Vitamin D – remember that even a rock-solid Paleo diet won’t protect you from deficiency because most Vitamin D comes from sun exposure, not from food. And hyaluronan is may also be helpful, especially considering that we probably evolved to eat a lot more of it than we do.
If dry skin is a constant issue for you, try fish (for the Vitamin D and Omega-3s), or better yet, go outside and get into some sunlight! For hyaluronan, make a big batch of bone broth. It's not the only factor in skin health, but it really can help.