In this 4-part series, Janet Farrar Worthington talks with PCF-funded researchers Lorelei Mucci and June Chan to uncover the latest science around food, exercise, and prostate cancer.
What does it mean to live your best life? You might say, quite reasonably, that your best life does not include prostate cancer. That’s a goal that we share at PCF – for you to live your best life free of prostate cancer. Regardless of where you are in your journey – prevention, treatment, recovery, or survivorship – there are things you can do to be pro-active toward this goal.
What can you do to maximize the good, to help your physical and mental wellbeing? There’s actually quite a lot. For example: Exercise not only helps you lose weight; it helps fight depression, and it even can help slow down prostate cancer! And eating the right diet – as opposed to eating a lot of junk and chemicals – can boost your spirits, your energy level, and just generally make you feel better. Most importantly for prostate cancer, certain foods can help lower chronic inflammation and insulin that fuel prostate cancer growth, and, in addition, can help your body fight or prevent any number of chronic diseases that are also driven by chronic inflammation. The good news is that it goes both ways: there is growing evidence that the lifestyle choices that keep you safe from other diseases – such as eating low sugar for diabetes, or exercising for your heart – can also help prevent or curtail prostate cancer.
First, Why Studying Diet is Hard
Research on food as medicine is the hardest area in which to do controlled, rigorous research in all of medical science. PCF-funded epidemiologists June Chan, Sc.D., of UCSF and Lorelei Mucci, M.P.H., Sc.D., of Harvard both study lifestyle factors and their effect on prostate cancer. Even though many late-night TV ads might try to tell you otherwise, there are no single magic bullet diet prescriptions for disease. None.
Both of these experts will tell you right off the bat that studying food is hard. In many studies over the years, scientists have tried to isolate specific foods to see if they promote or prevent cancer; they do that by asking people to recall what they ate over certain periods of time or keep a food journal. Such studies take a long time, and are not without their share of problems. For example, even if you isolate certain foods that seem promising, there is still a lot of variation! Let’s say you notice a trend in those who didn’t get cancer: they eat apples (hypothetically!). What kind of apples? Is it all apples, or just Granny Smiths? Were they all grown in the same type of soil? Were they cooked, or eaten raw? Peeled or not? Organic or not? How many did people eat a day?
But wait! Did these people even have an actual benefit from eating the apple – say, one they brought to work from home – or did they benefit from not eating a bag of cheese puffs or Twinkies from the vending machine instead? And wait some more! Do the people who benefited have genetic or molecular differences that make them more likely to be helped by apples? Or… are people who eat apples also more likely to exercise and take better care of their health in general – so maybe it’s not even the apples but their whole lifestyle that made the difference, and we’re back to the drawing board! This is why you might notice that science around nutrition takes time; or you might see it evolve over time as scientists “factor out” more variables. Remember back in 2010 when coffee was bad? And now here we are in 2020 and coffee is good? It doesn’t mean that scientists were wrong in 2010: it just means that now we know more, a decade later.
Broad Strokes are Better
There are a confusing number of variables in food science, so researchers don’t yet have a Paint-by-Number approach, with every single food accounted for. Instead, today’s food science is painting with some broad – but definitive – strokes.
Chan and Mucci both cite work led by Harvard scientists Fred Tabung, Ph.D., M.S.P.H., and Edward Giovannucci, M.D., Sc.D., that look at the relationship between diet and inflammation. In the study, the scientists tracked inflammatory markers in the blood and whether inflammation was raised or lowered by what people ate, based on data from thousands of participants in the Nurses’ Health Study and the Health Professionals Follow-Up Study. The key lies in the foods they found that significantly reduce chronic inflammation: dark yellow vegetables (carrots, winter squash, sweet potatoes, etc.); leafy green vegetables (like spinach, broccoli, kale, etc.), coffee, and wine. Beer (one bottle, glass, or can) was in this category, too. So was tea, but its effect was not very strong.
The pro-inflammatory (aka bad) category included processed meats (hot dogs, bacon, pepperoni, lunch meat, etc.), red meat, refined grains, high-energy beverages (with additives and sweeteners), and “other vegetables,” like potatoes and corn. Interestingly, not all fish is equal: canned tuna, shrimp, lobster, scallops, and “other” fish were more inflammatory than “dark-meat” fish like salmon or red snapper.
But if you love canned tuna, and if you love a baked potato or corn on the cob, don’t freak out: remember, broad strokes! The key seems to be to make sure you DO eat the anti-inflammatory foods. For example, the anti-inflammatory effects of leafy green vegetables, dark yellow vegetables, wine and coffee are more powerful than the very mild, pro-inflammatory effect of “other fish” or “other vegetables.” If you feel like you just can’t give up meat entirely, that’s okay too: just aim for small portions of meat, surrounded by a rainbow of anti-inflammatory vegetables.
For more information on an anti-inflammatory diet, download The Science of Living Well, Beyond Cancer.
Coming soon: Part 2 – What’s Good For Your Prostate is Good for All of You!