Living longer and staying healthier. It’s HealthyTalk with Dr. Michael Smith, M.D. Here’s your host, Dr. Mike.

DR. MIKE: Based on some new research, the combination of vitamin D and Metformin, the diabetic drug, could be quite effective in preventing colon cancer. This is really important because 70% of cases of colon cancer are thought to be preventable really through just dietary and lifestyle modifications. Seventy percent preventable – colon cancer. It makes sense that we are doing more research into these types of lifestyle supplement nutrition studies to prevent colon cancer which has plateaued in the United States over the past few years, but still remains a significant cancer for people in this country. I think the best way for us to approach this is to first talk about what are the common risk factors for colon cancer. It will make more sense than, at that point, to go into the study. You’ll understand why vitamin D and Metformin were studied as potential preventions.

Let’s look at some of these common risk factors for colon cancer. First of all, let’s start with lifestyle: diet, a diet high in red meat. Especially cows that are eating grain. They have a higher Omega 6 content that is going to raise inflammation. If you are doing grass-fed beef, that is probably better, but red meat, conventional red meat from conventional farms – not good. If you are eating 80% animal protein and 20% plant – not good. Low physical activity. Obesity. Of course, smoking. Smoking increases the risk of just about every type of disease. Alcohol consumption – to a point. We know that one to two drinks a day can be beneficial. But there is a point of diminished returns for alcohol consumption. Then there is a point where it becomes detrimental. Insomnia – in recent studies has been shown to be a risk factor. There are some basic lifestyle things that increase your risk for colon cancer. Genetics and family history play a role as well. About 75% of colon cancer cases are considered sporadic, meaning that they happen in somebody with no family history of colon cancer but 25% seem to be inherited. In at least 25%, we can find another family member that has colon cancer. We do believe that there is a genetic predisposition here. We also know that certain disorders like when you have a lot of polyps in the colon – it’s called familial adenomatous polyposis. In some cases, you could have hundreds and hundreds of polyps in the colon. That tends to run in families and that tends to increase the risk of colon cancer. So, there is what seems to be a genetic and family history link in at least 25% of the cases. Obviously, high levels of inflammation. About a month ago I talked about the use of aspirin in certain cancers. Aspirin, of course, is an anti-inflammatory. It has some great affects in helping people have improved outcomes in colon cancer because you are reducing inflammation. We know that the inflammatory enzymes, cyclooxygenase. These are highly active in colon cancer. If we can calm those enzymes down, maybe we can prevent colon cancer but also treat it with things like aspirin and curcumin and boswellia. Those would be some more natural choices. We also know that low folic acid levels – as a matter of fact 13 studies including over 725,000 subjects showed that people with the lowest amount of B vitamins and folic acid had a 15% increase risk of colon cancer. Low foliate, low B vitamins increases the risk. Here is where it really gets interesting. There are two other lifestyle types of risk factors - metabolic syndrome and low vitamin D. Metabolic syndrome is a collection of different symptoms: low good cholesterol, high triglycerides, high sugar – often pre-diabetes or diabetes - blood pressure issues, obesity – that’s metabolic syndrome. Often many diabetics fall into this category. That is a risk factor. As a matter of fact, it says here, “Higher levels of insulin and glucose in the blood can increase the risk of developing colorectal cancers. A study that reviewed different trials from 1966 to 2005 found that a diagnosis of diabetes raised the risk of colon cancer by more than 30% in both men and women.” Metabolic syndrome is connected to colon cancer and also low vitamin D levels. There was a review of nine studies that found for every ten nanograms per mil increase in serum vitamin D, the relative risk of colon cancer decreases 15%. So, if you all of these different risk factors and we consider that many of the cases of colon cancers are completely preventable because of these types of risk factors.

It makes sense, then, that there were a group of researchers out of China that looked at vitamin D and Metformin as a way to prevent colon cancer. Vitamin D will obviously correct the low vitamin D levels and the Metformin can correct the glucose and insulin issues seen in metabolic syndrome. So, it makes sense that they studied this. This was published in February 2015 in the issue of Cancer Prevention Research. The researchers from China started with the hypothesis that vitamin D helps to regulate cell proliferation, differentiation and program cell death - apoptosis. A normal cell will divide and specialize into a colon cell and as it gets older it does kill itself – apoptosis. Vitamin D regulates a lot of that process. We also know that Metformin is an AMPK activator which helps in those same processes as well. The hypothesis here is that vitamin D and Metformin can work together, synergistically, to improve cell division, cell growth, cell differentiation. They administered varying doses of vitamin D and Metformin for 18 weeks to rats that were given a compound that renders the colon very susceptible to the development of colon cancer. The rats were given a compound that basically causes colon cancer. And then they gave that compound in the context of vitamin D and Metformin. In comparison with vitamin D and Metformin alone the combination of a moderate dose of vitamin D and Metformin resulted in the formation of fewer abnormal areas, abnormal cells, abnormal polyps and tumors in both experiments. That is really encouraging. Here you have, granted, a rat study – I often talk about rat studies. It’s okay. We’ve got to start somewhere. Animal models are fine. Rats actually have a very close physiology to us. Here you have a situation where the rats were given a compound that is known to cause colon cancer. They were given vitamin D or Metformin or a combination of both. The combination of both working on that hypothesis that they will work synergistically together to improve cell differentiation and growth and apoptosis will prevent the development of cancer. That is exactly what happened. And it was just moderate dosing of vitamin D and Metformin. This really does open up the possibility for more research looking at vitamin D and Metformin as a combination, especially in people at high risk for colon cancer.

This is Healthy Talk on RadioMD.

I’m Dr. Mike. Stay well.