Fats & oils are some of the most
misunderstood nutrients in today's health community. Conventional
wisdom teaches us to cook with 'light' polyunsaturated oils, while
saturated fats have been all but demonized. Yet heart disease continues
to be the
leading cause of death in the US, and
chronic inflammation has been identified as a contributor to diseases like arthritis, cancer, diabetes and Alzheimer's.
New
research suggests that perhaps not all the blame lies with the
type of
fats we're eating (saturated or not), but their
quality and
chemical
stability.
Free radicals contribute to inflammation, so fats that are susceptible to oxidation are particularly dangerous.
To
understand which fats are most easily oxidized, a quick chemistry
refresher: each type of fat (saturated, monounsaturated, or
polyunsaturated) has a different chemical structure. Saturated fats are
structurally rigid because every carbon molecule is "saturated" with a
hydrogen molecule. Monounsaturated fats have one "unsaturated" carbon,
which forms a double-bond to the next carbon atom on the chain.
Polyunsaturated fats have more than one double-bond.
Fats are most susceptible to oxidation at double-bonds. Therefore,
the more double-bonds a fat has - the more unsaturated it is - the more easily it will oxidize and create free radicals. And when you eat rancid fats or oils, their free radicals create
oxidative stress
in your body, contributing to aging, damaging blood vessels, increasing
inflammation and setting the stage for many degenerative conditions and
diseases.
Exposure to heat, light, and air hastens the rancidification process,
so cooking with unsaturated oils just increases the likelihood that
those oils will oxidize and cause health problems. Some unsaturated oils
are rancid before you even buy them: processing techniques can heat
them before they’re bottled, and clear packaging may allow further
damage from light. Saturated fats, on the other hand, are more stable
and can withstand higher heats. Perhaps this is why Great-Grandma always
cooked with butter or lard.
We tend to forget that
some saturated fats are healthy and necessary for good health.
According to Dr. Jeffrey Bland, “all saturated fat is not the same.
…Short-chain fatty acids (like butyric acid, which is highly
concentrated in butter) play such a critical role in supporting the
healthy of the intestinal cell lining” (Bland et. al., 2004). That said,
moderation is key. Saturated fats stiffen our cell membranes and affect
their permeability. This is important because cell membrane function
directly affects health or disease. According to Dr. Michael Murray,
“Alteration in cell membrane function is the central factor in the
development of virtually every disease. … Without the right type of fats
in cell membranes, cells simply do not function properly” (Murray,
Pizzorno & Pizzorno, 2005).
Now, this doesn’t mean that I
advocate removing unsaturated fats from your diet. They have many health
benefits, such as the anti-inflammatory effects of
omega-3 fatty acids
found in seafood, chia, flax and walnuts. I recommend getting healthy
unsaturated fats from whole foods like avocados, nuts and seeds. And
personally, I buy extra-virgin olive oil to drizzle on my salads.
The bottom line: if
you’re going to purchase unsaturated oils, ensure that they’re
cold-pressed and packaged in dark containers - and don’t use them for
cooking. Otherwise, rely on small amounts of saturated fats for cooking,
and ensure they're organic to avoid added hormones, pesticide residue,
and antibiotics.
Sources:
Bland, J., Costarella, L., Levin, B., Liska, D., Lukaczer, D., Schiltz, B., … Lerman, R. (2004). Clinical Nutrition: A Functional Approach. Gig Harbor, WA: The Institute for Functional Medicine
Murray, M., Pizzorno, J., & Pizzorno, L. (2005). The Encyclopedia of Healing Foods. New York: Atria.
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