My goodness, I'm so glad I chose nutrition as my profession - it never gets boring!
Today's latest news: nitrates (and nitrites) in food are worse than previously thought. A recent study at Brown University found that dietary nitrates are strong predictors of chronic disease such as Type II diabetes, Alzheimer's and Parkinson's. The study was published in the Journal of Alzheimer's Disease (Volume 17:3 July 2009). Nitrates are also known carcinogens, most linked to childhood cancers - if that wasn't bad enough.
Where do nitrates come from? Processed meats such as lunch meat (bologna, salami, pastrami), sausage, pepperoni, bacon, ham, and of course, America's favorite: hot dogs. Nitrates are also found to some degree in cheese and beer, although I believe they're most heavily concentrated in processed meats. Also, as nitrogen-based fertilizer use increases, nitrates are showing up at higher levels in all kinds of food (one more reason to buy organic - no chemical fertilizer with added nitrates).
So why are these food preservatives SO bad? For one they decrease oxygen circulation in our blood - which explains the link to Alzheimer's and Parkinson's disease. When oxygen rates to the brain decrease, brain cells die quickly and permanently. Nitrites actually bind with hemoglobin proteins in red blood cells, prohibiting the red blood cells from carrying oxygen, which leads to cell death throughout the body.
Nitrates and nitrites from food also form compounds in our body called nitrosamines. Nitrosamines are the actual carcinogens that are notorious for causing cancer. They may act similarly to free radicals by mutating cell DNA - always a bad idea.
The good news is foods naturally rich in vitamin C such as fruit and vegetables (especially locally grown, fresh and organic produce) help prevent the formation of nitrosamines from nitrates. So this is just one more mechanism that fruit and veggie consumption prevents cancer.
So let's all stay away from nitrates and nitrites by eating less (or no) processed meat and more fresh produce. And for you who already do, let this encourage you!