In fact, the situation of being overweight or obese in mainland China is not optimistic. The report shows that the annual growth rate of obesity in my country will be as high as 5.4% between 2020 and 2035; if no relevant measures are taken, almost 1 in 5 Chinese will be obese by 2035.
As one of the top ten chronic diseases identified by the World Health Organization, obesity will destroy people’s health like a “snowball”, including a series of complications, such as metabolic syndrome, diabetes, non-alcoholic fatty liver, cardiovascular diseases and cerebrovascular, cancer, etc. wait.
Recently, a study published in The Lancet Regional Health-Western Pacific revealed another major danger of obesity – the bigger the belly, the more brain damage!
This epidemiological analysis and a two-sample Mendelian randomized study in almost 10,000 Asians showed a causal relationship between high visceral fat and BMI and cognitive decline – specifically, visceral fat For every 0.27kg increase, cognitive ability will decline, which corresponds to a reduction of 0.7 years in cognitive age.
The researchers collected 8769 participants from the Singapore Health Life Cohort (HELIOS), and recorded their metabolic indicators and cognitive data.
Among them, body fat composition was measured using a DEXA whole-body scan, including 16 indices related to body fat and 14 metabolic parameters, to assess participants’ obesity and metabolism.
In this study, BMI>27.5kg/m^2 was defined as obesity. Statistics show that 23.3% of all participants are obese, and another 12% have a BMI greater than 30kg/m^2. However, there are slight differences in the prevalence of obesity and various chronic diseases among different Asian countries.
The evaluation of cognitive function adopts a computer test, which includes four sections, namely memory, executive function, processing speed and attention, and the cognitive index “g” is obtained through a comprehensive calculation.
Across the population, the “g” index was normally distributed; generally, there was a positive correlation between “g” and years of education (r = 0.35) and a negative correlation with age (r = -0.65).
Univariate analysis showed that four factors were most strongly associated with the “g” index, namely metabolic syndrome (β = −0.09), visceral fat (β = −0.07), high-density lipoprotein cholesterol (β = 0.07) and BMI (β = −0.05 ).
In other words, higher measures of metabolic syndrome, visceral fat, and BMI were associated with poorer cognitive performance; conversely, an increase in HDL cholesterol, a marker of metabolic health, was significantly associated with better cognitive performance.
In a further inverse variance-weighted Mendelian randomization, the researchers found a causal association between three major factors and cognitive function: visceral fat group (VAT), BMI, and BMI-adjusted waist-to-hip ratio.
Among them, the causal relationship of “more visceral fat leading to cognitive decline” was the strongest! For every 0.27kg increase in visceral fat, or every 4.52kg/m^2 increase in overall fat, the cognitive age will decrease by 0.7 years.
Higher BMI-adjusted waist circumference, blood pressure, triglycerides, glycemic index, and lower HDL cholesterol were not associated with altered cognitive function.
In conclusion, body fat content is one of the independent predictors of cognitive function in Asian populations. MR analysis revealed a causal relationship between increased visceral fat and BMI and decreased cognitive performance. Losing weight seems to have added a new benefit – “brain benefit and dementia prevention”!
The researchers emphasized that the global burden of dementia is shifting from the Western Hemisphere to the Asia-Pacific region. Around 4 million Asians suffer from dementia each year, accounting for around 40% of new cases worldwide. In addition, the prevalence of obesity in the Asia-Pacific region is 7% higher than the global average and is even increasing. Therefore, the prevention and management of obesity plays an important role in maintaining cognitive function and preventing dementia and other chronic diseases in Asian populations.
In fact, a randomized controlled study previously published in eLife conducted an 18-month lifestyle intervention on obese people, trying to prove that “weight loss can delay brain aging”.
Sure enough, in all 102 obese participants, under lifestyle modifications, each 1% weight loss resulted in a significantly younger brain age of 8.9 months! This effect is actually used! But how to change the habits of everyday life in order to have such a good effect?
After inclusion and exclusion criteria, a total of 102 participants were included in this study. At baseline, mean BMI and waist circumference (WC) were 30.1±2.5kg/m2 and 107.1±6.6cm, respectively, both meeting obesity criteria. Furthermore, the predicted baseline brain age was 52.8 ± 4 years.
After 18 months of lifestyle intervention, participants lost 2.31 (±5.61) kg in weight; while BMI and waist circumference decreased by 0.76 (±1.86) kg/m2 and 5.39 (±5.89) cm, respectively, compared to baseline by 6.45% and 4.35 %.
Further analysis revealed a correlation between changes in BMI and body weight and functional aging of the brain. Specifically, a 1 percent reduction in BMI or weight resulted in an 8.9 month reduction in the rate of brain aging!
In addition to BMI and body weight, the researchers found a direct relationship between all measures of fat deposition, as well as changes in superficial subcutaneous, visceral, and liver fat, and delayed brain aging. In other words, the more diet-induced fat, the younger the brain.
Lifestyle intervention is not a single point, but adjustments from all aspects. So, among the many diet and exercise lifestyle interventions, what factors have produced such “satisfactory” results?
Correlation analysis shows that a high intake of processed food and sweets / drinks is the “culprit” that causes accelerated aging in the brain! But a higher intake of polyphenol-containing foods, such as green tea and walnuts, did not reduce brain ageing.
In other words, in daily life, giving up junk food and sweets is the “golden key” to protect the brain!
As the researchers explain, high body weight causes fat-mediated neuronal damage, metabolic dysfunction, and changes in the gut microbiome; these changes cause inflammatory metabolic processes in the central nervous system, leading to reduced gray/white matter volume of the brain, altered connectivity, cognitive impairment, and an increased risk of dementia.
It should be noted that the normal range of BMI for adults in mainland China is 18.5≤BMI <24, ≥24 and ≥28 overweight and obese, respectively. For people who are overweight or obese, it is essential to develop a healthy lifestyle to lose fat (such as reducing the intake of processed foods and sugary drinks)!
In fact, regardless of whether the BMI is greater than the “point” of obesity, developing good eating and exercise habits can also effectively improve the cognitive function of the brain and reduce the incidence of dementia. It is also responsible for your own body, why not do it?
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Source: Mays Medicine
