2016 update: Myricetin is one of those magical flavonols that act as anti-oxidants in normal cells but selectively destroy cancer cells. In fact, among the flavonols, it may be tops at targeting cancer cells for destruction.
Put walnuts and their next of kin on your anti-cancer shopping list. And who might that be?
That would be pecans–their yummy southern sisters, the other outrageous nut of the Juglandaceae clan.
In studies of the health promoting effects of various nuts, pecans are running second best to walnuts. Check out these sources:
- comparison of anti-oxidants, phytonutrients, effects on growth of cancer cells
- comparison of phytonutrients and ability to act as anti-oxidants
- internet health guru explaining the studies (If you don’t want to watch the video, just click on “transcript.”)
Is it down to the basic elements?
As Dr. Michael Greger expIains in that post, scientists don’t know exactly why walnuts and pecans are so protective. Here’s my hunch. Both nuts contain large amounts of compounds that bind copper, an element that easily oxidizes and fuels cancer’s spread.
As you know from an earlier post, scientists have discovered that copper drives angiogenesis–the process by which cancer cells create blood vessels and then spread throughout the body. In fact, a drug that binds copper has shown promising results in clinical trials.
As you know from high school chemistry, when it comes to oxidation, copper is mighty promiscuous. So is iron. They readily hand out electrons from their outer shells, leaving unstable molecules called free radicals of oxygen, which go around stealing electrons from other molecules and compounds, thus triggering a chain of free radicals that stress your system. The result is internal rust.
That’s where anti-oxidants come in. They neutralize free radicals by supplying the missing electrons. But if you don’t have a continual supply of anti-oxidants to quell the little fires within, then your immune system goes into overdrive to help. That’s chronic low level inflammation. And according to many health experts, chronic inflammation underlies many modern diseases, cancer included.
Back to the nuts
Walnuts, and to a lesser degree, pecans, contain two important phytonutrients that seem to keep you from absorbing both copper and iron:
- myricetin, and
- ellagic acid, which affects iron and copper without disturbing zinc, an important anti-oxidant often missing in plant-based diets.
Ellagic acid, found in a relatively few plants, also has anti-inflammatory and anti-estrogenic properties. It inhibits aromatase, the enzyme that turns cholesterol into estrogen– important for all hormone-driven cancers, both male and female. And myricetin causes cancer cells to commit suicide–at least in the petri dish.
Plus English walnuts–the most common kind– have one more advantage. They’re rich in omega 3 fatty acids, which also fight inflammation. (They’ve got five times more than black walnuts and ten times more than pecans.)
And that brings us to the practical part.
How to treat your precious nuts
Omega 3s are very fragile. They oxidize easily when exposed to light or heat. You can tell that they’ve gone bad by that off taste or smell.
Choose nuts that have been protected from light and heat. Keep them in the fridge or freezer. Don’t roast English walnuts.
Avoid nuts packaged in plastic.(That’s where I often find the rancid ones. And we all know that chemicals from plastic leach into fats).
And eat the skins–the thin whitish outermost parts of the shelled walnut, where most of the phytonutrients reside.
As with all good things, more is not necessarily better. Many health experts are recommending we stick to a small handful a day on our anti-inflammatory, anti-cancer diets, not the entire bag–easier said than done, I admit, especially when you’re nuts for nuts.