Saturated fats, found
primarily in meat, cheese, and other full-fat dairy products, have long been
known to increase blood cholesterol and risk for heart disease. These fats generally increase inflammation in
the body. And, higher levels of
inflammation appear to increase risk for both heart disease and Alzheimer’s and
vascular dementia. Interestingly, a new
research trial has revealed a direct link between diets high in saturated fat
and risk for Alzheimer’s disease. In the study, researchers found that a diet
high in saturated fat markedly reduces level of a brain chemical important in
preventing the build-up of proteins in the brain associated with
Alzheimer’s.
The clinical trial, led
by Dr. Angela Hanson, involved 20 seniors with normal cognition and 27 with
mild thinking impairment, a precursor to Alzheimer's disease. The patients, all in their late 60’s, were
randomly assigned to diets that contained the same amount of calories but were
either high or low in saturated fat. The high-saturated-fat diets had 45% of
total energy coming from fat, including 13% from saturated fats. The low-saturated-fat
diets had 25% of energy coming from fat, with saturated fat contributing less
than 7% of total calories.
A build-up of beta
amyloid plaques in the brain is the hallmark of Alzheimer’s disease. The body chemical apolipoprotein E (ApoE) is
important in removing beta amyloids from the brain, preventing them from
accumulating and developing into damaging brain plaques. In this study, after just a month on the high
and low saturated fat diets, researchers measured significant changes in the
amounts of amyloid beta and ApoE in the study participants' cerebrospinal fluid. Participants who received a high-saturated-fat
diet showed a decrease in levels of helpful ApoE and an increase in amyloid
beta proteins. Conversely, those on the
low saturated fat diet showed a decline in levels of amyloid beta proteins.
Also, the diets appeared to cause greater changes in the levels of these
substances in adults with cognitive impairment than in those who had normal
brain function.
These findings only add
to a growing body of evidence indicating the same lifestyle factors that harm
the heart also harm the brain. Smoking,
extra weight, high cholesterol, diabetes, and inactivity are all associated
with greater rates of both heart disease and dementia. And, a heart healthy lifestyle appears not
only to reduce risk for Alzheimer’s and other forms of severe dementia but also
overall brain function. For example, a
recent study of nearly 3,800 people, aged 35 to 82, found that those with the
most risk factors for heart disease did 50% worse on mental functioning tests
(that assessed memory and mental skills such as the ability to plan and reason
and to begin and switch tasks) than
those with the lowest number of risk factors.
Smoking and diabetes were especially associated with poorer brain
function.
What to do:
Adopt a heart healthy lifestyle!
Aim for regular activity, a healthy weight, and a diet that is rich in
fruits, vegetables, and lean proteins (i.e. fish, skinless chicken, lowfat/nonfat
dairy, beans), moderate in calories, and low in saturated and trans fat. Remember saturated fats are found primarily
in meat, full fat dairy such as whole milk, cheese, cream, and butter, and
products prepared with lard, butter, or shortening. Check labels to choose products with little
or no saturated fat. Use chicken, fish,
or beans more often than meat and, when you do have meat, opt for lean cuts and
trim off visible fat. When having dairy,
choose lowfat or nonfat products. And,
when cooking, instead of butter, lard, or spreads, use healthy plant-based oils
such as olive, canola, and vegetable oil.
Sources:
Hanson AJ, Bayer-Carter JL, Green PS, et al. Effect
of apolipoprotein E genotype and diet on apolipoprotein E lipidation and
amyloid peptides: randomized clinical trial. JAMA
Neurology, June 17, 2013 DOI: 10.1001/jamaneurol.2013.396.
Available at: http://archneur.jamanetwork.com/article.aspx?articleid=1697444
Joosten
H, Van Eersel MEA, Gransevoort RT, et al.
Cardiovascular risk profile and cognitive function in young,
middle-aged, and elderly subjects. Stroke
AHA, May 2, 2013. DOI: 10.1161/STROKEAHA.111.000496. Available at: http://stroke.ahajournals.org/content/early/2013/05/02/STROKEAHA.111.000496.abstract
Adapted from articles available at:
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