Skin cancer is now the most commonly diagnosed cancer in the United States and much of the world.
And you may not know it, but there’s a scary link between the sun, diet, and skin cancer (1).
For this reason, many people have an interest in potential ways to protect our health.
This article will explain how the foods you eat can either enhance or significantly decrease your susceptibility to this increasingly prevalent disease.
What is Skin Cancer?
Firstly, there are three major types of skin cancer.
- Basal Cell Carcinoma
- Squamous Cell Carcinoma
Regarding basal cell and squamous cell carcinomas, these are the most common – and most curable – types of cancer.
However, the five-year survival rate can be as low as 17% for melanoma (1).
In this article, we are going to concentrate on melanoma.
What is Melanoma Skin Cancer?
Melanoma is an incredibly aggressive form of skin cancer, and unfortunately, its incidence is quickly rising.
In fact, the prevalence of the disease has more than doubled since the 1980s and is predicted to increase further in the next 15 years (2).
In short, melanoma is usually a cancer of the skin that starts in melanocytes.
Melanocytes are the cells that produce the pigment known as melanin that we can see in skin color, eyes, and also moles.
While the majority of health advice to prevent melanoma revolves around avoiding the sun, recent research is showing that there is so much more to consider than that.
Sun Exposure and Skin Cancer: Is the Sun Deadly?
To begin with, we should note that there is a clear, strong link between sunburn and risk of melanoma. This fact is not in debate.
Just to point out, this is specifically sunburning that is being discussed – not mere exposure to the sun.
In fact, I’ve always been a little suspicious about the advice to hide our skin from the sun completely, and liberally cover any exposed area with sunscreen.
After all, hasn’t the sun sustained human life for millions of years?
Similarly, this brings vitamin D into mind.
With this in mind, is there a possibility that some more recent changes in our lifestyle are causing the skyrocketing rates of melanoma?
Why have melanoma rates increased so significantly in the past few decades?
Does Bad Diet Promote and Cause Skin Cancer?
The link between diet and skin cancer is stronger than you may imagine.
In essence, there is a relationship between the food we eat, the sun, and skin cancer.
Also, there is a link between diet and skin cancer independently of the sun.
The Link Between Diet, Sun and Skin Cancer
Our skin has a certain amount of UV resistance naturally – we could call it a “natural sunblock.”
A significant example of this is the amount of polyunsaturated fats in our cells and our omega 3-6 ratio.
Both of these affect how stable our cells are and how resistant they are to oxidative damage from UV radiation.
To emphasize this point; a large body of evidence suggests omega-3 is an inhibitor of melanoma.
Conversely, the data implicate (excessive) omega-6 as a melanoma stimulator (15).
Given these points, we should choose the dietary fats we use carefully.
The Direct Link Between Diet and Skin Cancer
Different from the link involving the body’s interaction with sunlight, there is also a direct connection between diet and skin cancer too.
Chiefly, this relates to the way the food we eat can influence our body.
An example of this is that high blood sugar and insulin levels are a risk factor for many cancers.
Modern diets excessively high in sugar and refined flours provide an abundant supply of glucose, providing the ideal environment for cancer cells to thrive.
Do Omega-6 Vegetable Oils Raise Melanoma Risk?
Despite their “heart healthy” marketing slogan, refined vegetable oils are not good for our body.
On the downside, there is also evidence showing omega-6 vegetable oils make our skin more susceptible to UV damage from the sun (16).
It’s important to realize that the modern diet has a huge effect on these issues.
To begin with, throughout most of human history the omega 6:3 ratio was 1:1.
Shockingly, the average Western diet is now somewhere between 10:1 and 25:1 for omega-6 (19).
As a result, our body can not use enough omega-3.
Therefore, we miss out on its anti-inflammatory effects and protection against UV-induced damage.
How Do Vegetable Oils Cause Sunburn?
The first thing to remember is that when we consume fat, the different fats we eat compete for uptake into our cells.
Especially over the past few decades, dietary saturated fat and omega-3 intakes have fallen. At the same time, consumption of omega-6 has skyrocketed.
To put it another way; we have way more omega-6 stored in our skin’s cells.
Why is that bad exactly?
We should remember that omega-6 fatty acids are extremely susceptible to oxidation from heat and light (22).
Perhaps you have heard not to heat an oil too high, or that it should be kept in the dark? This advice is to protect the oil from oxidation.
This advice is to protect the oil from oxidation.
In the same manner, omega-6 fats are vulnerable to oxidize inside your body.
In other words; they are just as liable to oxidative damage inside or out of the body.
How Do the Sun’s UV Rays React With Omega-6?
Could omega-6 be the link between diet and skin cancer?
Now that we understand how unstable omega-6 is, we’ll look at what happens when it reacts with UV rays.
An interesting question no doubt, and one that researchers already came up with – and studied.
In this study, researchers fed hairless mice a variety of diets with increasing proportions of polyunsaturated fatty acids (PUFA).
The mice were then exposed to a chronic course of UV radiation to measure the results.
In general, the higher their dietary intake of PUFA, the more cancerous tumors the mice developed (23).
Interestingly, some mice were also fed a diet high in saturated fat in the study.
Comparatively, these mice had a much higher immunity to the UV radiation and didn’t develop cancer.
Summing up their findings, the authors suggested that their data suggests polyunsaturated fats enhance photocarcinogenesis (causation of cancer).
Going back to those omega ratio figures; most people have an imbalance of at least 10:1 omega-6.
Now imagine those people tanning themselves on the beach for hours, perhaps with a sense of false security because they have slathered themselves in sunscreen.
With this in mind, it’s not hard to see how fried foods and vegetable oils are contributing to the melanoma skin cancer epidemic.
Is a Lack of Polyphenols a Link Between Diet and Skin Cancer?
Oxidative stress (resulting in DNA damage) is a big player in the development of melanoma.
Unfortunately, rapidly rising cancer rates probably go hand-in-hand with the plummeting nutritional value of the average diet.
The average person now eats processed foods full of cheap, industrial ingredients. In fact, 61% of all calories in the US come from ultra-processed food (27).
Compared to the diets of our grandparents, this is shocking. Our ancestors always ate freshly prepared meals from real homemade foods.
Now, many people order fast food or just make heavily processed microwave meals.
As a result, our intake of polyphenols and other beneficial nutrients has fallen by a lot.
How Do Polyphenols Prevent Melanoma Skin Cancer?
While it would be incorrect to say that polyphenols prevent melanoma, they may help reduce the risk.
Many polyphenols found naturally in food “have demonstrated clear anticancer effects toward melanoma” (28).
In other words, your dietary choices either help prevent disease or provide it with better conditions to take hold.
What Causes Free Radicals?
Here are a few common contributors to free radicals in the body:
- Excessive exercise
- Lack of sleep
- Eating oxidized fats
- Sugar and excessive carbohydrate
- Excessive exposure to UV light.
- Other exposure to environmental or dietary toxins.
Where Can We Get Polyphenols?
Essentially, if you eat a diet full of fresh, whole foods, you will be consuming an adequate amount of polyphenols.
Usually, we can get these compounds in the greatest amount from plant foods – or foods that came from a plant.
A few common examples are fruit, vegetables, cacao, coffee, tea, and red wine.
Balanced Omega 3:6 Ratio Protects Against Melanoma
Balancing the omega 3-6 ratio is one of the first dietary steps to reduce melanoma risk.
In fact, it’s one of the first things you should do to minimize the risk of any disease.
To do this, here’s what you want to do:
- Remove vegetable oils high in polyunsaturated fats (check here)
- Avoid fried food in restaurants
- Eat fatty portions of fish at least three times per week (salmon and mackerel are both excellent)
- Check labels to make sure there are no vegetable oils.
- Preferably stop buying processed foods and emphasize real, fresh food from local markets.
- Don’t go crazy on natural foods high in omega-6 fats (e.g. nuts – a handful is enough).
A diet to help prevent melanoma – or any skin cancer – will have three things in common.
- It will contain zero or very small amounts of omega-6 vegetable oils
- There will be plenty of nutrient-dense foods consumed
- The diet will include sources of omega-3
In my mind, these are the big three in the link between diet and skin cancer.
5 Polyphenol-Rich Foods That Protect Against Melanoma
Here are five especially important foods and drinks that help strengthen the skin’s resistance to UV, reduce sunburn and protect against skin cancer risk.
- Salmon: Salmon firstly contains omega-3, which as we have discussed is extremely beneficial for strengthening the skin. Secondly, salmon contains a potent antioxidant called astaxanthin. In studies, “astaxanthin exhibited a pronounced photoprotective effect and counteracted all of the measured UVA-induced alterations to a significant extent” (29).
- Tomatoes: Tomatoes are another of the foods protective against skin cancer. Tomatoes contain lycopene, a vital antioxidant. A study investigated the results of a daily (40g) serving of tomato paste over ten weeks against a control group. Although there was no difference after 4 weeks, the tomato paste group had a 40% better resistance to UV radiation at week 10 (30). This progressive improvement is also a good reminder; we should get into healthy dietary habits every day, not just occasionally! Good health is a continuous journey.
- Dark Chocolate: You may not know it, but cacao is one of the most nutrient-dense foods in the world. Long-term consumption of cocoa increases our skin’s UV resistance (31, 32).
- Tea: Both green and black teas offer an excellent range of polyphenols that help reduce the risk of sunburn. Black tea appeared to show a protective effect against melanoma in a study from Italy, whereas fruit and vegetables did not (33). Additionally, numerous studies report that green tea reduces cancer risk (34).
- Coffee: As the biggest source of polyphenols in the modern American diet, coffee has a wealth of health benefits (35, 36). Furthermore, research shows that coffee could play a significant role in the link between diet and skin cancer. Several studies demonstrate a “statistically significant” inverse risk to melanoma (and all skin cancers) in coffee drinkers (37, 38, 39, 40).
In the long run, there are lots of things that can increase or reduce our risk of skin cancer.
These include sunburn, getting enough sunshine (vitamin D is necessary!), and as with any cancer; focusing on healthy living in our everyday lives.
The link between diet and skin cancer is strong, though.
The main points to remember are keeping an optimal omega 6:3 balance and emphasizing nutrient-dense foods on a daily basis.