From Colin Champ, MD’s blog:
Several years back a scientific article revealed that those of us with high “muscular strength” have a lower risk of becoming a victim to cancer – a 40% lower risk to be exact.1 After assessment of almost 9,000 men aged 20-82, scientists found that men with a stronger one-rep max on bench press and leg press have a 40% reduction in their risk of dying from cancer. They adjusted for body mass index (BMI), body fat, and cardiorespiratory fitness and the results still held strong (pun intended).2 In other words, there is something about simply being stronger that can lower our risk of getting cancer. Many felt as though there was something innately healthy about having more muscles, but another study associated weak hand grip strength with an increased risk of cancer, even regardless of muscle size.3 So is it all about strength or do muscles fight cancer?
Strength goes beyond lowering our risk of dying from cancer; it lowers our risk of dying from most major health issues. For instance, men exhibiting a lower vertical leap, less sit-ups, and decreased grip strength have a higher risk of dying period.4 Men and women with moderate and high bench press and sit-up scores have lower risks of death,5 while men with a higher 1-repetition bench and leg press apparently live longer (even when we account for other health issues, like cardiovascular disease, smoking, obesity, etc.).6
Muscles Fight Cancer – More Muscles = More Health?
The first thought that comes to mind is that more muscles means more strength, and both are a result of more exercise. Sure enough, when we take a close look through these studies, we do see that the strongest among us have less body fat, are in better shape, and have better “good” cholesterol values with lower blood sugar and triglycerides.1 This is not surprising.
However, in nearly all these “muscles fight cancer” studies, other health issues were adjusted for and the findings still held. In other words, these studies seem to suggest that strength is independently associated with a lower risk of cancer and a higher change of avoiding an untimely death, regardless of age, smoking, alcohol usage, or other health issues. But as we know, associations can only take us so far, before we must explore the mechanism that support these associations.
Muscles Fight Cancer – It’s the Muscles!
In the study above, the scientists found some intriguing results: the benefits of muscular strength overlap with cardiovascular fitness, but the benefits of muscular strength in decreasing the risk of cancer death work through different mechanisms.1 Perhaps the synergy exists, or in other words, having more muscle and strength is good, and exercising them is better.
For instance, we know that exercising our muscles leads to:
Improved insulin sensitivity (less insulin needed to remove sugar from our blood)
More sugar extracted from our blood by skeletal muscle and used for energy during exercise
Less cancer-promoting sugar and insulin floating around our blood
A decrease in the levels of hormones that, over a prolonged period, can lead to cancer. For instance, resistance training increases IGFBP-3, which binds to insulin-like growth factor (IGF), decreasing its ability to promote cancer (growth factors are normal within the human body, but too many can lead to excessive cellular growth, including cancer growth)7
Decreased inflammation (which when present, serves as a fertilizer for cancer)
Increased antioxidant defense, which helps fight potential cancer-causing free-radicals
Less inflammation-producing body fat
However, recent studies have changed much of our thinking when it comes to muscle. There are many organs in our body that respond to stimuli and secrete hormones, which serve as messages to direct remote parts of the body. We are recently starting to find some more unconventional organ-like structures in the body. For instance, it is now well-established that our adipose tissue works like an endocrine organ – albeit a bad one – secreting inflammatory hormones and an excess of potentially cancer-stimulating hormones.8 Take estrogen for example, which is a hormone that both men and women require to function normally. However, when supplied in higher than physiologically normal amounts from excess body fat, it can increase a woman’s risk of breast cancer. When women lose theses additional pounds through dietary changes and exercise, estrogen levels decrease.9
Studies have now shown that fat is not the only recently discovered endocrine organ. Muscle may act similarly, though this time to the benefit of our health. The metabolic muscular organ within us secretes IL-6, an important cytokine that was once felt to be a bad guy that caused inflammation. Newer studies reveal that IL-6 has a healthy role and is actually a myokine, which is an endocrine hormone produced by muscle (myo = muscle) and released during contraction. In other words, while fat secretes harmful hormones, muscles squeeze out some healthy hormones during lifting.
You can read the rest at his site referenced above. He is a radiation oncologist and stays up on what’s new in cancer and ways we can fight this disease.
He gives us the Warburg effect from the early 1900’s. These things decrease cancer and its hold on us.:
Muscle contraction during exercise,16,17 with the more intense exercise resulting in increased expression of AMPK18
Carbohydrate restriction (with or without fasting and even in the face of an increase in calories)19
There is much on complex chemical processes in our bodies and how these all work together to make us healthy or sick. Good article on muscles making us fight cancer!!