Nutrition CUTTING-EDGE RESEARCH By Steve Blechman and Tom Fahey, E.D.
LEFT: GETTY IMAGES; TOP;JASON BREEZE38 MD musculardevelopment.com July 2019
Is Your Potassium
in Balance?
Nerve signals and muscle contractions
depend on movements of chemicals called
electrolytes that include sodium, potassium
and chloride. Cells regulate the electrical
potential of their membranes by maintaining
greater levels of sodium and chloride on the
outside and potassium on the inside. The
American diet, particularly the popular low-
carbohydrate diet, is high in salt (sodium
and chloride) and low in potassium. This
can cause calcium and bone loss, muscle
cramping, high blood pressure and heart
rhythm disturbances. Some bodybuilders
who take anabolic steroids oft en take
diuretics to avoid swelling, which can cause
loss of potassium. Increase potassium
intake by eating plenty of fresh fruits and
vegetables. Potassium-rich foods include
leafy green vegetables such as spinach,
romaine and cabbage; vine-grown foods
like tomatoes, cucumbers, zucchini, winter
squash and pumpkin; root vegetables like
carrots, radishes and onions; and fruits
like bananas, strawberries, apricots and
oranges. Milk, yogurt, potatoes, died peas
and beans also have healthy doses of
potassium. (The New York Ti mes)HIGH-PROTEIN DIET
Promotes Fat Loss,
Improves Insulin
Sensitivity
Health professionals worry that high-
protein, low-carbohydrate diets may harm
kidney and liver function and impair calcium
balance and insulin sensitivity. French
scientists found that rats fed a high-protein
diet for six months lost nearly 50 percent
more fat and 20 percent more bodyweight
than rats fed a high-carbohydrate diet. The
high-protein diet group had lower levels of
insulin, triglycerides (blood fats), the stress
hormone cortisol as well as blood sugar,
and showed no changes in kidney or liver
function. High-protein diets during short-
term treatment in rats appear healthy and
safe. The researchers said high-protein
diets could prevent the metabolic syndrome:
insulin resistance and high insulin levels that
lead to abdominal fat deposition, high blood
pressure, diabetes, high cholesterol and
blood-clott ing abnormalities. The metabolic
syndrome increases the risk of heart disease
and stroke and some kinds of cancer. (Am J
Physiol Regul Integr Comp Physiol, Articles
in Press)Harvard Nutrition professor Dr. Edward
Giovannucci petitioned the U.S. Food and Drug
Administration (FDA) not to allow a health
claim on food labels that high calcium intake
reduces the risk of prostate cancer. He said the
claim is based on one case study and ignores
considerable evidence that excessive calcium
intake actually increases the risk of prostate
cancer. In the Harvard Physicians’ Health Study,
men who consumed two servings a day of milk
or other dairy products were 30 percent more
likely to develop prostate cancer than those
who ate less than half of a serving per day. The
study examined nearly 21,000 male doctors.
Researchers speculate that the calcium content
of dairy food may play a role in developing
prostate cancer. Milk may deplete the body of
a special ty pe of vitamin D that helps protect
the prostate. In another study, taking dietary
calcium supplements increased prostate cancer
risk by 70 percent. Many people take calcium
supplements to prevent bone loss and promote
weight loss. There may be a downside. An
important lesson for health-conscious people
is not to change your health habits based on
information from one or two studies. (Nutrition
Labeling Watch)HIGH CALCIUM
I N TA K E :
POSSIBLE PROSTATE
CANCER RISK
Best Diet
Composition for
Bodybuilders
Like almost all athletes,
bodybuilders divide the
year into competitive and
non-competitive periods.
They need plenty of calories
and protein to promote muscle growth
during non-competitive building phases.
During the pre-competition phase (six to
12 weeks before a contest), athletes strive
to lose fat and maintain muscle mass. The
optimal diet composition during all times
of the year should be 55 to 60 percent
carbohydrates, 25 to 30 percent protein and 15
to 20 percent fat, with reduced calorie intake
prior to competition. Many bodybuilders
follow a low-carbohydrate diet during the
pre-competition phase, which is incorrect.
Athletes must train intensely to maintain
muscle mass and cut fat. The body requires
carbs to exercise above 65 percent of
maximum eff ort. Carbohydrate intake should
be high enough to fuel intense training.
Athletes who follow an Atkins-ty pe diet (low
in carbs and high in protein and fat) may lose
weight rapidly, but can’t train as hard. Also,
simple sugars (with protein) are essential
for recovery from intense workouts, so have
simple and complex carbohydrates in your
diet. (Sports Med 34: 317-327)