Nutrients 2019, 11, 522; doi:10.3390/nu11030522 —
Cantoral A, Contreras-Manzano A, Luna-Villa L,
assess the consumption of dietary fructose according to: 1) classification
of hepatic steatosis by two indexes and 2) diagnosis of NAFLD by MRI.
- Previous studies have shown that consumption of
fructose through soft drinks and other beverages is higher in NAFLD
patients than in controls.
- Mexico has one of the highest per capita intake
of soft drinks worldwide and their consumption is particularly high in the
19 to 29 year-old age group.
- The present study sought to compare the intakes
of different dietary sources of fructose in relation to two liver indexes
that predict hepatic steatosis and the identification of NAFLD by MRI in
young adults in Mexico.
- A cross-sectional analysis was performed in a
sample of 100 healthy young adults living in Mexico City between October
of 2016 and May of 2017. Participants were selected from the Early Life
Exposure in Mexico to Environmental Toxicants (ELEMENT) cohort study.
- For the present study, participants were
evaluated during a weekend day at the research center after 10 hours of
fasting. A blood sample and anthropometric measures were obtained. In
order to estimate the hepatic triglyceride content, proton magnetic
resonance spectroscopy (PMRS) was performed. Also, a trained nutritionist
administered a validated semi-quantitative food frequency questionnaire
(FFQ) and a lifestyle questionnaire.
- Measurement of liver fat content and diagnosis
of NAFLD was made by MRI, and a fasting blood sample was obtained to
quantify glucose, triglycerides and hepatic enzymes (ALT, AST, GGT) using
a bench clinical chemistry analyzer.
The Hepatic Steatosis Index (HSI) was estimated using the ALT/AST
ratio, BMI, sex, and impaired fasting glucose (IFG) blood levels (>110
- The study sample had a mean age of 21 years,
54% were male, 52% were classified as low SES and 56% of participants were
not physically active.
- According to the MRI, 18% of the participants
had the diagnosis of NAFLD (>5% of triglyceride content in the hepatocytes),
and according to HSI and FLI, 44% and 46% of the participants presented hepatic
- The comparison between the true positive
participants and the healthy participants showed that the true positive
participants had an elevated risk in almost all the parameters in a higher
level. When comparing those
classified as false positive versus those in the healthy category, BMI was
2.3 to 3 times higher in the false positive group according to the HSI and
- For the false positive participants in the FLI
the risk is significantly higher in the variable ALT (RRR = 1.10, 95%CI
1.02–1.20) compared to healthy participants.
- For the total sample, dietary information
showed that the median energy intake was 2689 Kcal with approximately 56%
of the calories from carbohydrates, 33% from lipids, and 13% from proteins.
The median intake of SSB was 720 mL, with the main contributor to SSB
being soda (specifically cola-type) which contributed 45% of the total
SSB, followed by sugar-sweetened commercial fruit beverages and home-made
fruit beverages with 22%.
- Those with negative FLI (score < 30)
consumed statistically less energy (kcal) and total grams of carbohydrates
per day, but also reported consuming more calories from proteins and
lipids as a percentage of the total calories, compared to those classified
as positive FLI (score ≥ 30) and also compared to those classified as
- The dietary intake of almost all dietary
sources of fructose were higher in those classified with steatosis by both
- When the consumption of the different beverages
included in the SSB category was compared, the soda intake was
statistically higher in FLI false positive than in negative subjects. In the case of those classified as NAFLD,
the median intake of natural fruit juices was statistically higher
compared to those classified as non-NAFLD (146 versus 0 mL/day).
- Sugar-sweetened beverages (SSB) and juices were
consumed significantly more by those with steatosis by FLI and NAFLD
suggesting that SSB intake is linked to metabolic alterations that predict
the risk of having NAFLD at a young age.
- This study adds to the existing evidence
linking SBB intake with NAFLD, a disease that is increasing in
Mexico. Therefore, more public
health action is needed to reduce the intake of fructose, as sucrose or
HFCS, especially from SSB that are highly consumed in Mexico and in other populations.
- As obesity is currently one of the biggest
health problems in Mexico, and it is related to the incidence of NAFLD,
more studies are needed to measure the prevalence of NAFLD in relation to
Points to Consider
- The limited sample size and the cross-sectional nature of this
analysis limits the ability to draw conclusions regarding the effect of increased
fructose consumption, mainly through SSB, on the natural history or progression
of NAFLD in this population.
- It is possible that other lifestyle factors, such as overall diet,
obesity and sedentary behavior, may have an equal of higher effect on NAFLD
classification. Given the design of this study, it is not possible to isolate
the effect of a single factor. Further, no conclusions about cause and effect
can be drawn.