The Singapore Chinese Health Study (SCHS) is a scientific study comprising one of the largest Asian population-based cohorts in the world comprising over 60,000 middle-aged and elderly Chinese Singaporeans with data collected over the space of 20 years.
The SCHS is led by the National University of Singapore’s Professor Koh Woon Puay, and has measured its participants based on their dietary patterns to study the determinants of chronic diseases including cognitive decline, most prominently based on their adherence to the Dietary Approaches to Stop Hypertension (DASH) diet.
The DASH diet emphasises increased consumption of healthier foods such as fruits, vegetables and grains as well as the reduced consumption of items such as red meats and sodium.
“One thing we know for sure is that the prevention of cognitive decline is critical to individuals being able to enjoy the healthy ageing process,” Prof Koh told the floor at the recent Growth Asia 2023 Summit.
“Over the course of 20 years from the 1993/1998 period to 2014/2016 period, we collected data from participants from an average age of 53 until the average age of 73 based on their adherence to the DASH diet.”
Participants were given DASH scores where higher scores were considered better adherence to the diet, and also scored via the Mini-Mental State Examination (MMSE) questionnaire to evaluate cognitive impairment, with high scores also considered better cognitive function and this was converted into an odds ratio scale indicating the likelihood of impairment in the future.
It was found that not only did those with persistently high DASH adherence scores have a lower risk of developing cognitive impairments, but those that opted to make healthier lifestyle and diet changes later in life also saw improvements when they improved their DASH scores.
“Most prominently, we found that when it comes to the risk of developing cognitive impairments, participants that [improved and maintained] dietary changes from their middle-aged to later years [were able] to reduce their risk of cognitive impairment,” she said.
“Participants with consistently high DASH scores has just a 0.67 score on the odds ratio scale of getting cognitive impairment in the future, compared to the consistently low scorers with a score of 1.
“However, those who made medium to large increases of 10% or more in their DASH scores through very significant changes to their diets saw their risk scores drop to 0.72 - showing that the risk can still be decreased with these dietary changes.
“The key takeaway here is that at any age, making the switch to a healthy diet can help to reduce the risk of cognitive impairment in later life, and thus improve the process of healthy ageing, so it is really never too late to make the change.”
East vs West
Prof Koh also highlighted that the positive impacts of dietary pattern improvements revolving around the DASH diet on cognitive health have been studied quite thoroughly in Western populations, but the SCHS was established to obtain more localised data.
“We realised there was a strong need to have our own study in this region due to the many dietary differences between here and western consumers, which means that data obtained from those studies might not accurately represent populations here,” she said.
“These include differences in the types of vegetables, fruits, whole grains, nuts and legumes being eaten here – think of items such as meats e.g. roast chicken vs char siew (roast pork); or desserts such as ice cream vs red bean soup, and the differences in ingredients used and the nutrients involved are very obvious.
“This is in addition to our higher intake of refined grains such as white rice and noodles, as well as different cooking styles and quantities consumed on an average day – so an independent Asian study was certainly very important to gather local data.”