Feed
Your Brain: The Mind-Body Connection
By Susan
M. Kleiner
Depression is
the leading cause of disability in the United States. It
can manifest in several forms, from major depressive symptoms
easily identified as a clinical disorder to mild, chronic
symptoms that can persist for several years. According to
the National Institute of Mental Health figures from 2001,
major depression affects nearly twice as many women (6.7
million) as men. Mild, chronic depressive symptoms affect
approximately 5.4 percent of the U.S. population age 18
and older at some time during their lifetime. This translates
to about 10.9 million American adults and often begins in
childhood, adolescence or early adulthood.
Women who have had an episode of depression have increased
odds of developing a cluster of conditions including abdominal
obesity, high blood pressure, elevated blood sugar and unhealthy
cholesterol levels. Commonly referred to as “metabolic
syndrome”, these conditions set the stage for type
2 diabetes, heart disease and stroke. Not surprising, really.
When you’re depressed you don’t take care of
yourself. Depressed people are more likely to smoke, eat
an unhealthy diet, stop exercising and not comply with medical
treatment.
Conversely, studies also show that obesity increases the
risk for depression. Once you are overweight you have a
greater chance of becoming depressed which may thwart any
efforts that you make to improve your lifestyle and lose
weight; a vicious cycle.
Anti-Depression Foods
Changes in emotional state are initiated in the brain. Chemicals
called neurotransmitters control communication between brain
cells, and connect the circuits and structures of the brain
to elicit mood states. Depression is believed to be due
to the low availability and/or dysfunction of neurotransmitters.
Serotonin is the most significant and well-understood neurotransmitter.
When levels of serotonin drop, mood is depressed. When serotonin
can’t act effectively to allow for cell to cell communication,
symptoms of depression rise. Drugs like Prozac and Effexor
increase serotonin concentrations in the brain, improving
mood and reducing depression.
How you attend to your physical and psychological health
directly affects the concentrations of serotonin in your
brain. You are probably well aware that diet, activity,
rest and stress reduction techniques all play a significant
role in your overall health. These factors impact mood because
they elevate levels of serotonin. In fact, there are specific
foods that can affect your mood and can be used to target
anti-depression. If you are mildly depressed, foods may
be just as effective as drugs in elevating concentrations
of brain serotonin without the negative side effects.
Turkey and Milk
Tryptophan, an amino acid, is the chemical precursor to
serotonin. The production of serotonin in your brain is
limited by how much tryptophan is available in your bloodstream.
Since tryptophan is an amino acid it is found in protein-containing
foods. But only certain foods are especially high in tryptophan
and have been shown to elevate blood levels of tryptophan
and brain levels of serotonin.
Studies on subjects who are prone to the effects of stress
have investigated the impact that diets high in whey protein,
a naturally rich source of tryptophan, have on their stress
response, mood and cognitive performance. The results of
two studies have shown decreased physiological responses
to stress, improved mood and memory performance as a result
of increased brain tryptophan and serotonin activity from
a diet high in whey protein. Although the healthy subjects
who were not overly prone to stress did not gain the same
level of benefit, it seems clear that even mildly depressed
individuals could benefit from this small dietary change.
Dairy foods are high in whey protein. The best sources are
reduced fat and fat-free milk, yogurt, cottage cheese and
dairy beverages like kefir. Turkey is another good source
of tryptophan. These foods are a smart addition to an anti-depression
diet.
Whole Grains, Fruits, Vegetables and Legumes
Tryptophan can only become a building block of serotonin
once it crosses the blood-brain barrier. Oddly enough, it
isn’t the level of protein in the diet that is the
gatekeeper of the crossing, but the level of dietary carbohydrate.
In the bloodstream, tryptophan competes with other structurally
similar amino acids, called large neutral amino acids (LNAA)
for a spot on the carrier molecule that transports them
across the blood-brain barrier. When protein intake is high
there is an abundance of similar amino acids and competition
for spots is equally as high, limiting tryptophan’s
access into the brain. When protein intake is lower and
carbohydrate intake higher, then there is less competition
for the spots on the carrier molecule right off the bat.
Carbohydrate gives tryptophan an additional advantage by
stimulating a series of biochemical events that removes
most of the LNAAs from the bloodstream placing them into
muscle cells, except for tryptophan. Carbohydrate-rich diets
give tryptophan a competitive edge to cross the blood-brain
barrier, elevating brain concentrations of serotonin and
enhancing mood.
Several studies have documented that diets containing at
least 40 percent of calories from carbohydrates can have
mood-improving effects on clinically depressed subjects.
These diet-induced alterations in mood are less pronounced
in healthy subjects. Research has also shown that low- to
moderate-glycemic index carbohydrates are the best choices
for control of mood state. High glycemic index carbohydrates
lead to peaks and valleys in insulin secretion, leading
to diminished levels of brain serotonin.
Fish, Flax and Eggs
Sixty percent of the brain consists of fats in the membranes
of brain cells. Polyunsaturated fatty acids (PUFA) in the
membranes surrounding brain cells play a role in every step
of serotonin function – serotonin production, degradation,
release, reuptake and binding with receptors. In order to
keep mood elevated, serotonin has to carry messages between
brain cells. This requires that the cell membrane be relatively
fluid. It is the concentration of PUFAs in brain cells that
determine the fluidity of the membrane. High concentrations
of omega-3 fats, a type of PUFA, in the part of the brain
cell membrane that closely adjoins another cell, indicate
that they play a critical role in membrane fluidity and
cell communication.
A recent study examining the association between depression
and selected nutritional factors found lower red blood cell
levels of PUFAs, including omega-3 and omega-6 fatty acids,
in depressed women when compared to healthy women. They
also found significantly lower levels of alpha-linolenic
acid (ALA) and linoleic acid, two essential fatty acids.
These findings support the results of several earlier studies.
Phospholipids are fat-containing compounds that play pivotal
roles in the brain. They determine the flow of nutrients
in and out of the cell and influence cell communication.
The two important phospholipids are phosphatidylcholine
(PC) and phosphatidylserine (PS). These two compounds can
deteriorate as we age, and reduced cellular levels of PC
and PS may be associated with diminished memory and cognitive
function, and even Alzheimer’s disease.
A study conducted in 1998 investigated the influence of
total dietary fat on mood. During the first month of the
study all subjects ate a diet consisting of 41 percent of
the calories from fat. During the second month half of the
subjects switched to a 25 percent fat diet. Following the
second month levels of anger and hostility were elevated
in the low-fat group. Tension and anxiety was decreased
in the higher fat group. HDL-cholesterol levels improved
on the higher fat diet and declined on the low fat diet.
No other changes in cholesterol profile were observed.
When designing an anti-depression diet, keep the dietary
intake of total fats at 25 percent of calories or more.
Increase your intake of omega-3 fats by eating fatty fish,
including wild salmon, black cod and shellfish. Flaxseed
and hempseed oil are the best dietary sources of ALA. Lecithin
is the best dietary source of PC and PS. Add an egg yolk,
soy and unrefined oils to boost your lecithin intake.
Other foods and supplements
Other nutrients under observation for their influence on
mood are vitamin D, the B vitamins and vitamins E and C.
Vitamin D boosts serotonin levels. The best sources of vitamin
D are fortified dairy and soy products, and spending 15
minutes exposed to the sunshine every day.
Some studies suggest that B vitamins, especially, thiamin,
niacin, folate and vitamin B12 may improve mood and cognitive
function. Enjoy your B vitamins from whole and enriched
grains, legumes, meats and leafy greens.
Vitamins E and C are important antioxidants that protect
brain cells. They may play crucial roles in slowing memory
loss due to aging or Alzheimer’s disease.
Numerous supplements are under study for their influence
on mood. The best data comes from the studies on fish oil
supplements and supplements of omega-3 fats. In addition
to including foods high in these nutrients, supplements
may be a convenient strategy for achieving optimum levels
of intake. Because fish oils can be contaminated, make sure
to buy from a manufacturer that guarantees a high quality
product.
Other supplements on the horizon include St. John’s
Wort, kava, L-tyrosine, Rhodiola rosea, ginseng, creatine,
acetyl-L-carnitine, ashwagandha, Huperzine A and vinpocetine.
Some have more data to support their use than others, as
well as more safety data. While St. John’s Wort is
a prescribed anti-depressant in many areas of the world,
it may interfere with other medications and it is not effective
for severe depression. For any of these supplements, consult
with your physician prior to experimenting on yourself.
Feed your brain and your body will follow
When you feel good it’s easier to control your body
weight. Most people eat when they feel lousy. When you’re
feeling mentally energized and your mood is lifted, food
is no longer the satiety that you are looking for. You are
more interested in being active, going outside, interacting
with others or even finding your creative outlet. Focus
first on eating to feel good. If you feed your brain and
your mood is lifted, you will stick to your nutrition plan.
And if you stick to your plan and you need to lose weight,
you will.
The old saying, “I’ll feel better when I lose
weight” is backward. You’ve got to feel better
first. Then you can feel great while you lose weight, and
for the rest of your life!
Susan Kleiner Bio, PhD, RD, FACN, CNS,
FISSN
Susan M. Kleiner is a leading nutrition authority on eating
for strength, and her POWER EATING® program has reshaped
the lives of thousands. Owner of HIGH PERFORMANCE NUTRITION™,
a consulting firm specializing in media communications,
industry consulting and personal counselling, she works
out of an office on Mercer Island, Washington, USA. Susan
is a member of the Can-Fit-Pro Advisory Panel.
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