Modest Visceral Fat Gain Causes Endothelial Dysfunction in Healthy Humans
Key result
Modest weight gain of ~4 kg impairs endothelial function in healthy volunteers.
- P=0.003
- n=43
Why the study?
Endothelial dysfunction independently predicts cardiovascular events, but whether fat gain impairs endothelial function was unknown.
Does modest weight gain impair endothelial function in normal-weight healthy humans?
Key Points
- This study aims to explore how modest fat gain influences endothelial function in healthy, lean individuals.
- Randomized controlled study with 43 normal-weight volunteers (mean age 29 years) assigned to gain or maintain weight.
- Endothelial function was evaluated using brachial artery flow-mediated dilation (FMD) before and after an 8-week fat gain period.
- Body composition was assessed through dual-energy X-ray absorptiometry and abdominal CT scans.
- Fat gainers increased their total, visceral, and subcutaneous fat (average gain of 4.1 kg).
- FMD decreased in fat gainers from 9.1±3% to 7.8±3.2% (p=0.003) and returned to baseline after weight loss.
- A significant correlation was found between decrease in FMD and increase in visceral fat (rho=-0.42, p=0.004).
Study Design
Type
RCT (n=43)
Randomization
randomized
Structured PICO
Does modest weight gain impair endothelial function in normal-weight healthy humans?
P
Population
43 normal-weight healthy volunteers (mean age 29 years; 18 women)
I
Intervention
Weight gain of approximately 4 kg over 8 weeks
C
Comparator
Weight maintenance over 8 weeks
O
Outcome
Endothelial function measured by brachial artery flow-mediated dilation (FMD) at 8 weekssurrogate
Main Result
p-value: p=0.003
Modest visceral fat gain impairs endothelial function in healthy young subjects, an effect that is reversible with weight loss.
Key expert perspectives
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“The effects of obesity on heart health receives a lot of attention, but less scrutiny has been given to the impact on the endothelium of modest weight gain in otherwise healthy people. In fact, many adults accept this kind of weight gain -- 9 or 10 pounds -- as just part of aging. The assumption has generally been that a modest rise in body fat was more an issue of going up a clothing size, not a health issue. This study suggests otherwise, providing evidence that may help change our cultural attitude to the implications of modest weight gain as we age -- and perhaps strengthen the argument for diet and exercise to control weight as a means of protecting against cardiovascular disease.”
ARAbel Romero-CorralPhysician researcher, Mayo Clinic
“There are three parts to the take-home message here: One is that in healthy people, modest weight gain results in impaired endothelial function -- even in the absence of changes in blood pressure. The second is the encouraging news: endothelial function recovers after weight loss. The third point is that it is visceral fat -- the abdominal fat that surrounds internal organs -- rather than fat deposited as subcutaneous fat, just under the skin, that predicts endothelial dysfunction.”
Implication
Clinicians should caution lean adults against modest weight gain; extends evidence that visceral fat causally and reversibly impairs endothelial function.
Abstract
This study sought to determine the impact of fat gain and its distribution on endothelial function in lean healthy humans. Endothelial dysfunction has been identified as an independent predictor of cardiovascular events. Whether fat gain impairs endothelial function is unknown. A randomized controlled study to assess the effects of fat gain on endothelial function. We recruited 43 normal weight healthy volunteers (mean age 29 years; 18 women). Subjects were assigned to gain weight (approximately 4 kg) (n=35) or to maintain weight (n=8). Endothelial function (brachial artery flow mediated dilation -FMD) was measured at baseline, after fat gain (8 weeks) and after weight loss (16 weeks) for fat-gainers and at baseline and follow-up (8 weeks) for weight-maintainers. Body composition was measured by DXA and abdominal CT scans. After an average weight gain of 4.1 kg, fat-gainers significantly increased their total, visceral and subcutaneous fat. Blood pressure and overnight polysomnography did not change after fat gain or loss. FMD remained unchanged in weight-maintainers. FMD decreased in fat-gainers (9.1 ± 3% vs. 7.8 ± 3.2%, p =0.003), but recovered to baseline when subjects shed the gained weight. There was a significant correlation between the decrease in FMD and the increase in visceral fat gain (rho = −0.42, p=0.004), but not with subcutaneous fat gain (rho = −0.22, p=0.15). In normal weight healthy young subjects, modest fat gain results in impaired endothelial function, even in the absence of changes in blood pressure. Endothelial function recovers after weight loss. Increased visceral rather than subcutaneous fat predicts endothelial dysfunction.
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Cite This Study
Romero‐Corral et al. (2010) conducted an RCT in Healthy volunteers (n=43). Weight gain vs. Weight maintenance was evaluated on Endothelial function (brachial artery flow-mediated dilation) (p=0.003). Modest weight gain of approximately 4 kg in healthy volunteers significantly impaired endothelial function, with flow-mediated dilation decreasing from 9.1% to 7.8% (p=0.003).