The Truth about Genetics and Disease: Is it Nature, or Nurture?

The FDA recently approved 23andMe’s genetic test which screens for breast cancer. The move was heralded as a great advancement in the field of direct-to-consumer genetic testing. Many people purchased the test, hoping it would reveal whether or not they would get breast cancer.

However, in its approval, the FDA also mentioned some serious limitations of the test. For one, it only tests for 3 of thousands of known mutations. If any other spot in the BRCA gene is mutated, the test would show negative when you actually do have a higher risk. But more importantly than that, the BRCA mutations they screen for are “rarely found” in the general population. Even those of Ashkenazi Jewish descent, who experience a higher rate of the mutation, only find it in around 2% of the population.

This means, very simply, that the overwhelming majority of users will receive negative results. This can actually be a very bad thing for your health. As noted by prominent researchers, an increase in direct-to-consumer testing has led to a decrease in actual preventative health services. After seeing Angelina Jolie perform a preventative mastectomy upon receiving positive genetic screening results, many people seemed to take away the opposite message. They somehow decided that a negative DNA test kit result meant they no longer had to get regular screenings.

What many of these folks failed to realize is that only a small percentage of breast cancers is caused by mutations in the BRCA gene. Less than 0.1% of the population has BRCA mutations, yet the breast cancer incidence is nearly 2% in a general population. Clearly, many breast cancer cases are caused by something other than a single gene.

Other Diseases Also Rely on Environmental Factors

Many other cancers and diseases are much the same. They are impacted by a wide variety of genes, and oftentimes the real cause gets buried in a sea of reductionist scientific studies. However, scientists have known for a long time that there are many things a person can do to reduce their risk of cancer, regardless of their genetics. These include things like quitting smoking (or never starting), exercising regularly, and other common-sense practices.

However, diet is also a very important area which heavily influences diseases like cancer, heart disease, diabetes, and auto-immune diseases. For most people, it makes a lot more sense to add some green veggies to your diet than to take an expensive DNA test which will likely be negative. Plus, there is plenty of evidence that eating more plant-based foods can drastically increase your wellbeing.

Can Eating Fruits and Veggies Fight Disease?

Your genetics are simply the blueprints for your body. But, the body must accumulate materials to use through the food that we eat. To grow, build new cells, repair damaged tissue, and otherwise function as a healthy person our body needs lots of different substances. These include fats, carbohydrates, and proteins. We don’t realize it, but the foods we eat contain these and other substances which our body must process.

Take the above incidence of breast cancer. While we know that only 1 in 1000 women actually have the BRCA mutation in their genes, many more than that will get breast cancer. Breast cancer risk factors, besides genetics, include high cholesterol and high levels of reproductive hormones in the body. Both of these are highly related to diet. Scientists have found that eating a plant-based diet can reduce both blood cholesterol and estrogen levels in the bloodstream.

Moreover, scientists have found that a 17% decrease in estrogen levels can account for a huge difference in breast cancer rates. Given that a plant-based diet can reduce your estrogen level 26-63%, this would significantly lower your chances of getting breast cancer. This significant decrease in your chance of getting breast cancer is often much greater than the increased risk presented by having BRCA 1 or 2 mutations.

But that is just for breast cancer. A whole-foods, plant-based diet has several unique components that are lacking from the typical “Western” diet, which are crucial to maintaining a healthy body and digestive system.

How Healthy Foods Fight Disease


One of the single most important components of a healthy diet is fiber. Adults in the majority of well-developed countries suffer from massive shortages of fiber. Fiber intake has been shown to be directly related to diseases such as colon cancer, diabetes, and even heart disease. Further, studies have shown that this fiber cannot be simply added back into the diet as a nutritional supplement to get the full benefits.

Fiber, in plants, is all the undigestable materials present. Every plant cell wall is composed of cellulose, a substance which is not fully digestible. This and other forms of fiber play an important role in human digestion, as they aid in the movement of food through the gut. The human gut is extremely long – several times the length of the body – and has evolved to slowly digest plant fibers. Meat, while it can be digested, is often digested too quickly for all the nutrients to be properly extracted.

Vitamins and Minerals

Though it has been shown that both plants and animal products contain a wide variety of vitamins, minerals, and other substances, plants are often more digestible. That means that the vitamins and minerals in plants are more likely to end up in your body.

For instance, have you ever heard of the slogan, “Milk grows strong bones!”? This, and other slogans like it are build on reductionist science. Scientists found calcium was involved in bone growth and maintenance. They also found that milk has calcium. So, they said through a variety of slogans and advertisements that milk was good for bone health.

But, there is strong evidence to the contrary. Countries which consume the highest amounts of dairy products are typically the countries with the highest rates of hip fractures and other bone density issues in old age. Upon further inspection, scientists found that increases in milk consumption tended to increase the acidity of the blood. In turn, this draws calcium out of the bones to compensate and actually makes bones weaker.

Plant-based foods do not increase the acidity of your blood, and plants like spinach have plenty of calcium for your body to use. This is true of almost every known vitamin and mineral that humans need in their diet. In getting the proper vitamins and minerals it needs, your body is much more likely to fend of diseases like cancer and autoimmune attacks.


Antioxidants are substances in food which have the ability to soak up free radicals. These damaging chemicals can travel through our body and cause damage to the DNA. These mutations can lead to cancer if not repaired, and the more free radicals in our body the faster the damage occurs.

The majority of antioxidants are created by and stored in plants. In eating your leafy green vegetables and juicy fruits, you are getting these antioxidants into your system and allowing them to work against a large variety of toxic chemicals affecting your body.

Regardless of which genetic mutations you carry, it takes a number of factors to actually cause cancer or other diseases. Antioxidants in your diet have been shown to reduce these risk factors, and plants are some of the best ways to get them into your system.



Campbell, T. C., & Campbell, T. M. (2006). The China study: the most comprehensive study of nutrition ever conducted and the startling implications for diet, weight loss and long-term health (1. paperback ed). Dallas, Tex: Benbella Books.

Commissioner, O. of the. (n.d.). Press Announcements – FDA authorizes, with special controls, direct-to-consumer test that reports three mutations in the BRCA breast cancer genes [WebContent]. Retrieved February 9, 2019, from

Gill, J., Obley, A. J., & Prasad, V. (2018). Direct-to-Consumer Genetic Testing: The Implications of the US FDA’s First Marketing Authorization for BRCA Mutation Testing. JAMA, 319(23), 2377–2378.



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Erika Bradey
Erika Bradey
4 years ago

I like that you mention how regular genetic screening can help with diagnosing cancers and diseases. In order to get accurate information, you’d probably want to research companies online to learn about their experience and the genetic screening services they offer. When researching, it would probably be a good idea to figure out which ones are in a convenient location and have hours that fit your schedule in order to find one that you can go to regularly.