Phoenix Acupuncture

The draw - and drawbacks - of raw

From the Los Angeles Times, July 30, 2007
By Susan Bowerman

Raw foodists show B12 deficiencies in studies. Supposed benefits are still
unproven.

Sylvester Graham, the health food advocate whose name we associate with the
snack cracker, suggested in 1839 that humans might never become ill if we
consumed only raw foods. Many people today would agree with him.

The growing interest in vegetarianism — driven by health and environmental
concerns — has spawned an offshoot known as the raw foods movement.

No exact definition exists, but raw food diets are often described as
“uncooked vegan diets” — which exclude all animal products and byproducts
– or more loosely as “uncooked vegetable diets” or “living foods” diets.
Adherents consume from half to virtually all of their foods raw. Aside from
fruits and vegetables, the diets include raw nuts and seeds and are rounded
out with sprouted grains and beans.

Those who aim to consume “living foods” do their best to eat foods as
quickly as possible after harvest. Devotees say that beneficial components
in plants — variously referred to as enzymes, energy or even a life force
– are destroyed when foods are heated above a temperature of about 118
degrees.

The number of raw foodists in the U.S. is unknown, and very little research
exists documenting their eating habits. In one report, interviews with 17
leaders in the movement indicated they had followed their diets for an
average of 13 years, and most consumed a diet consisting of at least 85% raw
foods.

They cited health as the primary driver in adopting the diet as well as a
number of perceived advantages, including disease prevention, faster
healing, weight control, better digestion, more energy and a greater
connection with nature.

Research has yet to prove whether raw food can provide all of these
benefits, but the diets have some potential shortcomings.

A raw vegan food plan may lack adequate protein and calcium and is likely to
be deficient in vitamin B12. A compound found naturally only in animal
foods, vitamin B12 protects nerve fibers and genetic material. In a recent
study of 201 raw foodists in the Netherlands, published in the Journal of
Nutrition, 38% were vitamin B12 deficient, and more than half had elevated
blood levels of homocysteine, an amino acid that requires vitamin B12 for
processing and that, when elevated, increases heart disease risk.

A diet rich in raw plant matter is bulky, filling and low in calories, so it
is not surprising that the adoption of a living foods diet is associated
with a substantial loss of weight. In one of the largest studies of
long-term raw foodists in Germany, published in the Annals of Nutrition &
Metabolism in 1999, 25% of women and nearly 15% of men were underweight.
Among women of childbearing age, 30% had disruptions or cessation of their
menstrual cycles — likely related to loss of weight and body fat.

It should be noted that the plant enzymes that raw foodists attempt to
preserve are no match for the highly acidic environment of the stomach.
There, they’re rendered inactive before digestion is complete. And some
phytonutrients, such as the brightly colored carotenoids found in tomatoes,
spinach and carrots, are not as readily absorbed from raw foods as they are
from cooked foods. Similarly, the magnesium, calcium, iron and zinc
naturally present in whole grains are released more thoroughly during
cooking.

Anthropologists Richard Wrangham and Nancy Lou Conklin-Brittain of Harvard
University say humans were meant to consume cooked foods. Heating foods
renders them more digestible — allowing better absorption of much-needed
calories.

They point out that humans have cooked foods for more than 250,000 years, a
time period long enough to produce biological adaptations — smaller teeth,
longer small intestines and smaller colons than our ancestors — in response
to eating a cooked-food diet.

Graham never got other food reformers of his time to rally behind him, but
perhaps the resurgence in interest will generate much-needed research on the
effects of a living foods diet.

Susan Bowerman is a registered dietitian and assistant director of the UCLA
Center for Human Nutrition.