Liver Fat Accumulation in Response to Overfeeding With a High-fat Diet

A Comparison Between South Asian and Caucasian Men

Siti N. Wulan; Vera B. Schrauwen-Hinderling; Klaas R. Westerterp; Guy Plasqui

Disclosures

Nutr Metab. 2015;12(18) 

In This Article

Background

The epidemic of overweight and obesity is one of the major public health problems not only in western countries but also in a number of Asian countries.[1,2] Globally, adult obesity is more common than under-nutrition affecting around 475 million adults who are obese, with over twice that number overweight. When Asian-specific cut-off points for the definition of obesity (body mass index >28 kg/m2) are taken into account, the number of adults considered obese globally is over 600 million.[3]

Differences in body composition between Asians and Caucasians matched for sex, BMI and age have been reported in several comparative studies. We[4] and others[5–9] found that Asians have a higher body fat percentage and a lower fat-free mass/appendicular skeletal muscle mass[10–12] compared to that of Caucasians. In addition, when the fat-free mass was corrected for body height, Asians were shown to have the lowest fat-free mass index (FFMI, in kg/m2) of ethnicities such as Hispanics, African-Americans and Caucasians.[13]

Among Asians, South Asians (people from Indian sub-continent) have the most pronounced difference in body fat[14] and an increased ectopic fat deposition in the liver[15] and muscle[5] compared to those in BMI-matched European Caucasians. It is hypothesized that South Asians have a lower capacity to store fat in subcutaneous adipocytes than Caucasians.[16] Excess fat may therefore overflow to the ectopic compartments, such as in the liver.[15] Thus, South Asians may be more susceptible to the negative effects of a high-fat diet. Ectopic fat accumulation in the liver has been shown to be associated with insulin resistance in Caucasians[17,18] and South Asians.[15]

It is well known that genetics may play a role and the interaction with environmental factors such as changes in lifestyle could increase the risk of developing the metabolic syndrome.[19] In Asia, the consumption of fat and added sugar in the diet have increased in recent decades.[20] The effect of a high fat diet on ectopic fat accumulation in the liver in Caucasian populations has been documented in some studies,[21–23] whereas IMCL (intramyocellular lipids) content increased in some studies[24] but not in others.[21] Van Herpen et al.[21] conducted a 3-week period of high fat isocaloric diet study with 60 % energy from fat and reported that the increase in liver fat was observed after 1 week with no further increase in the following weeks. In the present study, we induced liver fat accumulation with a high fat diet (60 % energy from fat) in a shorter time by overfeeding with 50 % excess energy than the requirement. Whether a high fat diet affects liver fat accumulation in South Asians and Caucasian similarly is unknown. A previous cross-sectional study[15] reported a higher liver fat content in South Asians compared to Caucasians after correcting for BMI, sex and age. As there is an ethnic-specific BMI-body fat percentage relationship,[8] in the present study South Asian and Caucasian men were matched for body fat percentage instead of BMI.

The objectives of the present study were to compare liver fat content at baseline between South Asian and Caucasian men matched for body fat percentage and to compare the increase in fat accumulation in the liver in response to short-term overfeeding with a high fat diet.

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