A Health at Every Size View on Prostate Cancer Research

In honor of Men’s Health in November, the small gland of the prostate gets big attention.

What Is Prostate Cancer?

Prostate cancer is the second most common cancer among men worldwide, after lung cancer. The prostate is a small gland in males that produces the fluid to transport sperm. There are different stages and medical treatments for prostate cancer, as well as screening tools. Right now, the scientific community has limited knowledge on the direct cause of cancer. As research is developed, the data can only show associations of trends that relate to one another. These factors associated with cancer are then further researched to explore prevention, causation, and treatments.

Nutrition, or food, as medicine is a theory that if we eat well, our risk of any disease is greatly reduced. Food has received much attention for promising cancer prevention and cancer recovery. One of the leading organizations, the American Institute of Cancer Research, or AICR, promotes individuals to take personal action towards prevention through a healthy eating pattern. They focus on nutrient research and cancer, in the hopes of finding a conclusion for prevention or treatment, or both.

What is the Relationship of Body Size and Prostate Cancer?

In the latest 2014 report, revised from 2007, reviewed 104 global studies that totals to nearly 10 million men with almost 200,00 men with prostate cancer. Experts concluded that there was strong evidence that an obese BMI was a significant risk factor for advanced prostate cancer. And yet, the report itself recognizes that BMI is unhelpful to determine fat mass.  Body mass index, BMI, is simply weight divided by height, squared. It was actually invented by someone not in healthcare and was never intended to be used for health data. BMI has so many limitations, and yet, research keeps using it like a bad habit because of human implicit bias and fatphobia.

In the data for BMI and prostate cancer, 24 studies on advanced prostate cancer were analyzed to conclude that for every 5 kg/m², there is a statistically significant 8% increased risk. So, if your BMI is 30, you divide that by 5, to get 6 and multiply by 8, to show a 48% risk for prostate cancer if your BMI is 30. So, this is not showing that 48% of 200,000 men had advanced prostate cancer.

Since BMI is not a health measurement, researchers went looking at other body measurements and risk. The researchers looked at waist circumference and waist-hip ratio, which are measurements that consider the abdominal region of the body. This is more specific than general body weight, and yet, these measurements also have their limitations on how health is defined. Again, implicit bias of fatphobia tells us that if someone has abdominal fat, then they cannot be healthy. Yet, only four studies were found and researchers concluded that for every 10 cm of waist circumference, there is a 12% increased risk of advanced prostate cancer. For waist-hip ratio, for every 0.1 unit, there is a 15% increased risk. The World Health Organization defines a healthy waist-hip ratio as 0.9 for men. What is interesting is that men are at risk in general. Notice how no matter your measurements, there is a risk associated. So, is that really about the fat? The numbers are not that convincing.

Does Diet Matter?

In the same 2014 report, there is limited evidence available to promote a specific diet, or eating pattern. Researchers explored dairy, high calcium diets, low Vitamin E levels, and low selenium levels and found limited evidence suggesting these certain foods or nutrients could increase risk. They also explored what food, nutrients, and supplements could be helpful, without conclusions. In general, an eating pattern that is health promoting, will include various types of foods. When there is a lack of food diversity, lack of fresh foods, fiber, and fluids, then it is possible not all nutrients are available to support adequate health. There is evidence that eating plenty of plant foods supports health in general. In the recent One Small Bite Podcast, David discusses more about specific nutrients of interest such as green tea, tomatoes, and soy, and whether or not they are helpful.

How does Weight Stigma Affect Health?

Researchers concluded that for men in large bodies, it is probable that there can be an increased risk of prostate cancer based on the strong association of body weight. However, this is still not a cause-and-effect conclusion – correlation is not causation. There is a huge opportunity for weight stigma here. Even if having a large body was a direct cause of prostate cancer, there is no reason to jump into weight loss diets.

Research also shows that weight stigma contributes to allostatic load, which is a term for the cumulative adaptation of multiple physical systems in the body. In other words, the more stigma given to people who are not within the “healthy” categories, the more that affects their health. For example, if a person experiences shame about themselves at the doctor’s office, they are less likely to come back to the doctor for routine check-ups.

Also, a large body is not a behavior. Research also shows that large bodies are mostly the result of biology and the environment, with behavior as a very small percentage. Biology and environmental factors are uncontrollable. What is an environmental factor? This can refer to many things, among them, the social determinants of health. Social determinants are a systematic barrier to health, which often get overlooked in studies that associate disease with large body size. Many studies that show association of large body size and disease do not account for social determinants of health, which are major factors for health.

The AICR’s own report concludes that the evidence does not support a judgment that a particular food, nutrition, or physical activity is likely to have a substantial causal relation to a cancer outcome.  In other words, food and physical activity is unlikely to be a causation of a cancer diagnosis. So, if we view food and physical activity as a choice, the AICR has yet to find a significant impact of anything in particular.

HAES Tips for Lowering Risk of Prostate Cancer

Aim for what you can control. Instead of trying to control your weight through weight loss goals, a more productive method is to explore your behavior, beliefs, attitudes, and environmental and genetic factors towards cancer risk. Strive for improvement instead of perfection, since perfection does not exist. Maybe there are some behaviors you can improve for your own health to lower risk. Or maybe you are too rigid with your eating unnecessarily. These are some anti-diet guidelines to lower your risk of prostate cancer:

1. No matter your weight, pursue regular medical check-ups. Get screened through PSA testing every three years for men over 40, and annually with your main provider for men over 55.
2. Eat cruciferous vegetables, berries, and fish often. Explore ways to make them taste good.
3. Find joyful movement. Physical activity is not a punishment.
4. If you smoke, quit. If you drink excessive alcohol, try cutting back. Find a program if you need support.
5. Find a provider who is respectful of all bodies and does not fat shame.

Bottom Line: while nutritiously dense foods are important for overall good health, there is no need to follow a ridge diet plan.

Written by Jennifer Baugh, RDN and reviewed by David Orozco, RDN