Fat is fat, right? Well, not exactly. All fat is not alike. It may surprise you to learn that there are two different kinds of fat, and one of them may actually increase the risk of prostate cancer.
Brown fat vs. white fat
The anatomic name for fat is adipose tissue. In itself, adipose tissue serves two positive functions: releasing energy and storing energy. The type of fat that releases energy is called Brown Adipose Tissue (brown fat) while the fat that stores it is called White Adipose Tissue (white fat).
Brown fat is more complex than white fat. It has a darker color because it contains many tiny blood vessels and iron-containing heat-burning elements called mitochondria. It is called “good fat” because it actually burns calories to generate heat. According to Dr. Pam Peeke, “Brown fat is derived from muscle tissue and is found primarily in hibernating animals and newborns. After life as an infant, the quantity of brown fat significantly decreases.”[i] Everyone has at least some brown fat, and it’s mostly located in the neck and shoulder region – though in some individuals it has been found in other places as well.
White fat, on the other hand, has few blood vessels and mitochondria, so it is light in color. You can think of white fat as energy storage (a way the body evolved in order to have energy reserves in times of food scarcity). But it does a lot more than that. As Dr. Peeke puts it, “It is a major endocrine organ, producing one form of estrogen as well as leptin, a hormone that helps regulate appetite and hunger. It’s also got receptors for insulin, growth hormone, adrenaline, and cortisol (stress hormone).” In addition, it acts as an insulator against cold and a “soft landing” against impact. Where is it located? Unlike brown fat, it has many more places in the body. In men, it primarily occupies the abdominal area (belly and waist) while in women it builds up in the hips, thighs, buttocks and breasts until midlife, when more white fat tends to accumulate in the abdomen.
Aging itself changes the ratio of brown-to-white fat. We have less brown fat and more white fat. The risk is not how much you weigh, it’s how much of your weight is composed of white fat. We all know that obesity is associated with cardiovascular disease and diabetes, and when you realize that white fat helps generate a cocktail of hormones that influence appetite, insulin use, and inflammation, the potential for danger begins to make sense. So how does this connect with prostate cancer?
White fat and the prostate gland
A recent study by Gucalp, et al. (2017)[ii] provides us with unique insight into the role that white fat plays in encouraging the development of aggressive forms of prostate cancer (PCa). They demonstrated that men with a higher Body Mass Index (BMI, a way of calculating obesity based on height and weight) had greater amounts of white fat around the prostate gland (periprostatic white fat) and that the fat itself showed signs of inflammation. To conduct their study, they enrolled 169 newly diagnosed PCa patients who were about to undergo radical prostatectomy. Pre-surgery BMI measurements and blood tests provided general information about factors such as cholesterol levels, blood sugar, and other metabolic information for each patient. Then, the surgery allowed them to collect the periprostatic white fat plus the cancerous prostate glands. Thus, they were able to analyze the fat for inflammation, and correlate all factors with tumor characteristics.
What they determined supports decades of observation that obese PCa patients tend to have more aggressive prostate cancer. Half of the patients (49.7%) had higher BMI, inflammation of the white fat, and larger amounts of it around their prostate gland. These patients had a significant correlation between higher BME and high Gleason grade tumors (Gleason grades 7-10). The fat inflammation itself correlated with high blood levels of insulin, triglycerides, leptin, and lower levels of the “good” cholesterol (HDL). Men with lower BMI and less fat inflammation had more favorable health factors.
As Dr. Mark Moyad so well stated, “Obesity is actually a situation that can cause chronic inflammation in the body and it probably increases the risk of aggressive prostate cancer, but also increases the risk of prostate cancer reccurrence.”[iii]
What can be done?
Obviously, achieving and maintaining a healthy weight has incredible implications for both brown and white fat. Even though we lose brown fat as we age, vigorous exercise (get that blood pumping!) encourages development of brown fat. In fact, people who live in cold climates have a bit of an edge, since exercising outdoors in the winter seems to foster the development of brown fat.
As for white fat, embracing a dietary lifestyle that avoids the so-called Western diet gradually influences the body to reduce the excess white fat that accumulates around the prostate gland (and other organs) as we put on pounds. See my blog, “Get Off the Western Diet Now!”
At the Sperling Prostate Center, we support a pro-health lifestyle (nutrition, exercise, stress management, work/life balance) for all patients. We know that taking care of overall wellness is the best protection for the prostate gland – especially knowing that when too much white fat surrounds the prostate, it’s no protection at all.
[iii] Moyad, M. “What the Heck has been Going on in My World?” Prostate Cancer Communication, Fall 2017 (Vol. 33, No. 2), pp. 8-16.