I, along with many of my friends, will tell you that I am a nerd. I get excited over really weird things. A lot of the things I get excited about revolve around science. The latest thing I've been intrigued by are polyphenols. Polyphenols are a class of phytochemicals (plant chemical) characterized by multiple benzenoid rings attached to hyroxyl (OH) groups (see picture on right, green tea phenol). These compounds are only found in plants and are intended to help protect plants from photosynthetic (sun) damage and protect against reactive oxygen species (hyperactive particles that damage DNA).
Here is where epigenetics comes in! (This may get a bit technical for some, I apologize). DNA can be modified via three different mechanisms: methylation (attachment of a methyl group, -CH3), histone modification (histones are proteins that DNA is wrapped around), and post-transcriptional gene modification by microRNAs. These processes affect gene product stability, DNA folding and complete nuclear organization of gene material. Although polyphenols affect each of these processes I want to focus on DNA methylation. When specific segments of DNA have too many methyl groups attached, the gene product of that DNA is 'silenced.' Conversely, when these regions have very few methyl groups attached they are active and produce gene products. It is now believed that hypermethylation (silencing) of tumor suppressor genes is one of the leading causes of tumor initiation and progression. In other words, it's a lack of signal from silenced DNA that tends to lead to cancer - not a new signal from active DNA. Think of the methyl groups as dumbbells - the more that are attached to the DNA, the more the DNA is weighed down and not able to replicate normally.
How do polyphenols fit in to all of this? Polyphenols actually directly inhibit the enzyme that attaches methyl groups to DNA. Therefore, they block gene silencing by keeping the DNA free from the dumbbells! They allow active tumor suppressor gens to keep being made (more tumor suppressor gene activity = more natural cancer defense).
The Lesson for Everyday Life
Polyphenols are essential for human health. With your new knowledge of the science behind polyphenols I'm sure you won't be surprised to learn that there is much evidence that suggests that populations with high pholyphenol intake have lower rates of all types of cancer. Now there are over 8,000 dietary polyphenols! Remember polyphenols are only found in plants (spices included). Listed below are just a few that have been found to help keep DNA free of methyl groups.
Various polyphenols from these and additional fruits, vegetables and spices have been found to inhibit the growth of MANY types of cancer cells in vitro (in lab conditions) including: breast, colon, prostate, cervical, lung, esophageal, skin, uterine, leukemia and lymphoma.
Keep in mind that drinks made from plants count too. Tea, coffee, soy milk and wine are actually great sources of polyphenols!
So, what little steps can you do add these protective compounds into your diet:
1. Add spices to foods. Instead of going for the salt shaker, try novel spices on your veggies. Sprinkle garlic powder, paprika, curry powder, dill or cumin on steamed veggies. One of my favorite things to do is to add a dash of cinnamon to my morning coffee. It gives it a different flavor and I'm getting the benefits of cinnamon (cinnamon also helps stabilize blood sugars).
2. Try to get the recommended number of servings of fruits and vegetables (newer recommendations are up to 9 servings!). Divide your plate in half, whether it be breakfast, lunch or dinner, and make sure that 1/2 of the plate is made up of fruits and/or vegetables. These foods also help keep you full longer because of their higher fiber content and increased water content compared to meats and carbohydrates. Now don't be overwhelmed by the number of servings. Serving size is what matters. One commercially harvested apple bought at a regular grocery store is large enough to be 2 servings. Only 1 cup of spinach or lettuce, a palmful, is a serving. You only need to have 4-5 spears of steamed broccoli to count as a serving. You really can get at least 5 servings/day by just eating a large piece of fruit and a medium-sized salad. Challenge yourself to try a new vegetable or fruit you have never had before at least once a month!
3. Choose green tea (unsweetened preferably) or coffee as your morning beverage.
4. Try soy! Edemame (soy beans that look like snap peas in their pod) and soy milk are great substitutes for meat and cow milk, respectively. I love vanilla soy milk in coffee and cereal!
Keep in mind that many other things in your environment can affect DNA function and that the research on how food compounds directly affect DNA is still in it's infancy. However, like I mentioned earlier we do know that populations that consume the highest amounts of fruits, vegetables (and other nutrient dense foods like whole grains and legumes) do have some of the lowest cancer rates. While there is still much to learn, there is little risk in incorporating polyphenol rich foods into your everyday diet!
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