CME for latest WUSTL study

[Guest guest]

The Continuing Medical Education (CME) information for the latest WUSTL human

CRers

studies is given below. It begins with a Reuters Health Information article and

then presents physicians with an interpretation of the studies regarding what

they

can learn from the report and the clinical relevance that the results represent

in

terms of their medical practice, it seems.

Calorie-Restricted Diet Curbs Normal Human Cardiovascular Aging CME

News Author: Rauscher

CME Author: Vega, MD, FAAFP

Disclosures

To earn CME credit, read the news brief along with the CME information that

follows

and answer the test questions.

Release Date: January 20, 2006; Valid for credit through January 20, 2007

Credits Available

Physicians - up to 0.25 AMA PRA Category 1 continuing medical education credits

for

physicians;

Family Physicians - up to 0.25 AAFP Prescribed continuing medical education

credits

for physicians

Jan. 20, 2006 — Adhering to a calorie-restricted diet over the long term

ameliorates

the normal age-related decline in diastolic function in healthy, non-obese

adults,

results of a new study indicate.

The cardiac-specific beneficial effects of caloric restriction appear to be

mediated

by reductions in blood pressure, systemic inflammation, and myocardial fibrosis,

the

study team reports in the January 17th issue of the Journal of the American

College

of Cardiology.

" This paper is important because it is the first study in humans that strongly

suggests that calorie restriction may delay primary aging, " Dr. Luigi Fontana

said

in a telephone interview with Reuters Health. Calorie restriction has previously

been shown to slow aging and increase lifespan in small mammals.

Dr. Fontana, an assistant professor of medicine at Washington University in St.

Louis, and colleagues performed Doppler echocardiography and measured

inflammatory

markers in 25 healthy adults who followed a severely calorie-restricted,

nutritionally balanced diet for an average of 6.5 years. Results were compared

with

those from 25 matched control subjects consuming a typical Western diet.

The calorie-restricted diet consisted of roughly 1,671 kcal per day derived

approximately 23% protein, 49% complex carbohydrates, and 28% fat (including 6%

saturated fat). The Western diet consisted of roughly 2,445 kcal per day made up

of

about 17% protein, 52% carbohydrates, and 31% fat (11% saturated fat).

The calorie-restricted diet included at least 100% of the recommended daily

intake

for all nutrients, and it was lower in salt than the Western diet.

Over the course of the study, the mean BMI of those on caloric restriction fell

from

23.9 to 19.7, although their weight was stable for at least 6 months at the time

of

cardiac assessment. None of them performed more than 20 minutes of vigorous

exercise

twice weekly.

According to Dr. Fontana, " people who followed a severe calorie-restricted diet

but

with optimal nutrition had a younger heart in terms of diastolic function, which

is

a well-accepted marker of primary aging because, independently of disease, as

you

get older your diastolic function gets worse and worse. "

Indictors of diastolic function were significantly better in the

calorie-restricted

participants than the Western diet group, the team reports. For example, the

early

filling fraction was 0.72 vs. 0.65, respectively, and the peak E-wave to peak

A-wave

ratio was 1.61 vs. 1.24.

As expected, there was no change in systolic function in either group.

Mean systolic and diastolic blood pressures were significantly lower in the

calorie-restricted group (102/61 vs. 131/83 mm Hg), as were levels of the

inflammatory markers C-reactive protein, TNF-alpha, and TGF-ß1.

Dr. Fontana and colleagues plan to continue to follow the study subjects " to see

if

other markers of aging are delayed in these people and determine the implication

for

health and the aging process. "

The author of a related editorial says that while it is not likely that many

individuals would adopt such a calorie-restricted diet, " the value of the study

is

that it points to possible mechanism explaining how aging occurs and, therefore,

how

it may be modified. "

" The authors, and the disciplined volunteers following the practice of caloric

restriction, are to be congratulated for their important contributions to this

effort, " Dr. Gerstenblith from s Hopkins Hospital in Baltimore adds.

J Am Coll Cardiol. 2006;47:398-404

Learning Objectives for This Educational Activity

Upon completion of this activity, participants will be able to:

Identify age-related changes in diastolic function.

Compare a calorie-restricted diet vs a typical Western diet in terms of

diastolic

function and intravascular inflammation.

Clinical Context

Aging affects diastolic function in some distinct ways. As patients grow older,

left

ventricular relaxation slows, and the role of early left ventricular filling by

suction is less prominent. Conversely, the role of atrial systole becomes more

critical in left ventricular filling. As opposed to diastolic function, left

ventricular systolic function is relatively unaffected by aging alone.

Calorie restriction has been demonstrated to reduce cardiovascular risk factors.

The

current study examines the effects of calorie restriction vs traditional Western

diet on echocardiographic findings and markers of intravascular inflammation.

Study Highlights

The researchers recruited 2 study populations: one group of adults who had

practiced

caloric restriction for 3 to 15 years, and another group who had eaten a

traditional

Western diet. Study subjects were generally healthy and were nonsmokers. All

subjects had stable weight for 6 months prior to study entry.

Participants reported food diaries for 7 consecutive days to confirm their

dietary

choices and evaluate dietary content.

Study outcomes included echocardiographic findings of cardiovascular function

and

intravascular markers of inflammation.

50 subjects entered the study. The mean age of participants was 54 years old,

and

84% of the cohort was male. The mean body mass index values were 27 and 19.7

kg/m2

in the Western diet and caloric restriction groups, respectively. As determined

by

dual-energy x-ray absorptiometry, the mean percentages of body fat were 26% and

9.3%, respectively.

The Western diet consumed an average of 2,445 kcal per day. The average daily

dietary content included 17% protein, 52% carbohydrate, 31% fat, and 11%

saturated

fat. The caloric restriction diet consumed an average of 1,671 kcal per day. The

average daily dietary content included 23% protein, 49% complex carbohydrate,

28%

fat, and 6% saturated fat. Salt intake was lower in the caloric restriction

group vs

the Western diet group.

There was no difference in left ventricle fractional shortening between groups.

The

early left ventricular filling fraction was greater in the caloric restriction

group. The Western diet group exhibited a delayed relaxation pattern of filling

vs

the caloric restriction group. The caloric restriction group had superior

evidence

of viscoelasticity of the left ventricle. Finally, left atrial velocity was

higher

in the Western diet group, suggesting that those patients were at higher risk

for

left atrial hypertrophy.

High-sensitivity C-reactive protein levels were 1.9 and 0.3 mg/L in the Western

diet

and caloric restriction groups, respectively. The respective levels of tumor

growth

factor-ß1 were 35.4 and 29.4 ng/mL, and the respective levels of tumor necrosis

factor-alpha were 1.5 and 0.8 pg/mL. All of these values were significantly

superior

in the caloric restriction group vs the Western diet group.

Pearls for Practice

Aging is associated with slower ventricular filling, reduced suction-induced

left

ventricular filling, and an increased role for atrial systole in left

ventricular

filling. However, aging in and of itself has less effect on systolic function.

The current study demonstrates that caloric restriction can preserve diastolic

function and intravascular markers of inflammation compared with a standard

Western diet.

-- Al Pater, PhD; email: old542000@...

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