You know that external factors are a major cause of aging. UV rays, pollution, and pore-clogging grime can all create inflammation and break down healthy skin and collagen. We often respond to these external assailants with external defenses. Certainly, sunscreens, serums, and other solutions are vital.

But taking steps to prepare your internal defenses is wise as well. Let me tell you about four of my favorite ways to slow aging from the inside out.

Of course, taking care of your insides starts with your diet. We all know that we need to eat healthful foods — just like we know that we should be wearing sunscreen. But unless you apply (and reapply) sunscreen perfectly every single day, some UV rays are bound to reach your skin. The good news is that you can offer your skin another source of protection.

Believe it or not, the foods you eat can reduce your risk of sunburn. In particular, carotenoids, which give fruits and vegetables their orange, yellow, or red color, can help. In addition to providing pigment to produce, carotenoids function as antioxidants in humans. That means they can scavenge the free radicals that create sunburns before they have time to do damage.

Researchers asked participants to eat a carotenoid-rich diet for 10 weeks. Then they measured their skin’s response to UV light. Sure enough, their likelihood of experiencing a sunburn decreased significantly.

Orange and yellow foods tend to be the highest in carotenoids, so start there. Try adding carrots or apricots to your regular rotation, along with a variety of other colorful fruits and vegetables.

I’ve yet to find a diet that can replace sunscreen. So you’ll still want to keep working toward your perfect record there. But carotenoids can help make up for any imperfections. And if you don’t end up needing them to fight UV rays, your body can always use some extra antioxidant support somewhere. You certainly won’t waste them!

How Sugar Destroys Your Skin

Now that you know what you should eat, let’s talk about what you shouldn’t: sugar. Sugar gets a well-deserved bad rap for a number of reasons. But I’d like to focus on its contribution to diabetes and obesity — and, as a result, aging skin.

As you may know, obesity can contribute to diabetes. And, of course, a high-sugar diet can be a significant factor in both conditions. But what does that have to do with aging?

Well, it turns out that obese-diabetic people often look much older than they are, according to a study conducted in Japan.

For this cross-sectional study, researchers enrolled 37 Japanese participants. Sixteen healthy-weight volunteers served as the controls. The other 21 were obese and diabetic. The researchers evaluated their skin according to several measures of aging.

They found some significant differences in how much aging the participants’ skin exhibited. The diabetic participants had less hydrated skin than members of the control group. Their skin lost water more quickly. And their collagen wasn’t as dense. Dry, sagging skin is definitely a recipe for an older appearance.

We can give much of the blame for these conditions to advanced glycation end products (AGEs). I’ve written about AGEs before — particularly how a high-sugar diet can create them. As you may recall, AGEs can break down collagen and create inflammation in the skin.

You can apply external products like vitamin C and moisturizer to fight the effects of AGEs. Those are certainly helpful. But it’s much better to minimize AGE production in the first place. You don’t want to end up like the participants in this study. Many of them were in their 40s, but their skin resembled that of senior citizens.

Cutting back on sugar is a great way to minimize AGEs — and aging. Your skin encounters enough enemies on the outside. Don’t subject it to attacks from the inside too.

I know you’re probably not happy to be thinking about giving up sugar. So let me tell you about another thing you can do to improve your skin that I bet you’ll actually enjoy: sleep.

Yes, Beauty Sleep Is Real!

If you’ve ever had a few nights in a row of poor sleep, I’m sure you noticed the effects showing up on your face. Dark circles and dullness are telltale signs of tossing and turning. But you may not have realized how much work your cells do when you are getting good rest.

When we sleep, we give our skin a reprieve from the radiation and environmental toxins that attack it during the day. And our skin cells use the downtime to repair any damage we’ve sustained while we were awake. When we’re asleep, our blood vessels expand. This brings more oxygen and nutrients to our cells, fueling the repair process.

If you don’t give your skin the rest it needs, it gets behind on its repair work. Damage starts to accumulate. And the less time you spend asleep, the more toxins you may be exposing your skin to.

Of course, applying some external products before you go to sleep gives our skin cells some extra tools to work with. At the very least, you’ll want to be sure you wash your face before bed to eliminate dirt and grime. If you don’t, your skin cells will be fighting off attacks from those toxins all night long rather than focusing on repairs.

Some people like to treat their evening skincare routine as a soothing signal that it’s time to wind down. I think that’s a great idea. Not only will that attitude help motivate you to give your skin extra repair tools, but it can also help you beat the fourth cause of inside-out aging I want to talk about: stress.

Keeping Stress-Related Damage to a Minimum

You know that stress can show up on your face just like a bad night’s sleep can. But that’s not the only place it can show up.

You may have thought that stress turning hair gray was just an old wives’ tale. But it’s true! And illness can make you go gray as well. Here’s why:

When the immune system senses an invader, like a virus, it starts producing signaling molecules called interferons. Interferons turn on genes needed to fight off the threat.

In the stem cells responsible for hair color, a transcription factor called MITF helps regulate the cells’ response to interferons. But when MITF gets overwhelmed, it can’t control the cells’ functioning properly. If MITF gets too busy dealing with interferons, hair color won’t get the attention it needs. And you’ll end up with grays.

Both stress and illness can trigger an immune response extreme enough to overwhelm MITF. This is especially likely if you’re already genetically predisposed to go gray. But you can help hold on to your natural color by supporting your immune system and reducing stress. You don’t want your immune system to overreact or be in the constant state of high alert that chronic stress can create.

If you’re following my earlier suggestion to get plenty of sleep, you’re definitely on the right track. Lack of sleep and excess stress can create a vicious cycle. Plus, they can motivate you to choose unhealthy high-sugar foods rather than beneficial fruits and vegetables.

This creates a perfect storm for your skin. Rather than using internal resources to handle the external attacks it faces, the skin has to defend itself from external and internal onslaughts. But healthy habits beget more healthy habits. Lowering stress can help you sleep better, shoring up your willpower when it comes to diet. These choices can be a great complement to any external skincare products you use.

There’s not a lot you can do about UV radiation or pollution, but you can give your skin the tools and environment it needs to deal with these attacks from the inside out. Cells that can focus on repair and restoration rather than fighting off invaders can be some of your best tools for slowing the aging process naturally.