Meal Time May Help Protect Against Cognitive Decline

Not only is most food delicious, but we need it, this is our fuel that provides us with the energy we need to function and remain healthy. Much research has been dedicated to investigating cardiovascular and metabolic health outcomes associated with when we eat as well as how food quality affects our health. But there is not a lot examining the distribution of energy influencing long-term cognitive health and whether it has an impact on the risk of dementia. 

Current estimates are that around 55 million people around the world are living with dementia with about 10 million new diagnoses annually. As the global population continues to age the proportion of older people affected by dementia is estimated to increase to 78 million people by 2030 and reach an astounding 139 million by 2050. 

This study examined the potential effects of energy intake and meal timing (temporal patterns of energy intake or TPEI) on cognitive decline. According to the researchers, consuming three balanced meals is associated with better cognitive function compared to a less evenly distributed way of consuming total energy intake (TEI). 

“To our knowledge, this study is one of the few population-based studies that explore the association of TPEI and cognitive decline, although accumulating studies have linked TPEI to health outcomes, including obesity, hypertension, and cardiovascular health,” the authors wrote.

The study included data from 3,342 people enrolled in the China Health and Nutrition Study with an average age of 62.2 years old. Those with severe cognitive decline were excluded from this study. Participants received dietary assessments and cognitive testing which was repeated four times over ten years, with scoring ranging from 0 for the lowest to 27 points for the highest level of cognitive health.

Participants were categorized into 6 eating patterns: 

• Evenly distributed: People balanced their energy intake across three roughly equivalent meals per day. They consumed 28.5% of their daily energy at breakfast, 36.3% at lunch, and 33.8% at dinner.
• Breakfast-dominant: People ate three meals, but consumed the greatest share of energy, 49.5% at breakfast.
• Lunch-dominant: People ate three meals, but consumed the greatest share of energy, 64.3% at lunch.
• Dinner-dominant: People ate three meals, but consumed the greatest share of energy, 64.5% at dinner.
• Snack-rich: People consumed 36.8% of their TEI from snacks.
• Breakfast-skipping: People ate little or no breakfast, consuming just 5.9% of their TEI.

Compared to an evenly distributed pattern the skipping breakfast pattern was linked to a cognitive decline of 0.14 points per year, according to the researchers. No other similar declines were observed for other patterns. But when the possible TPEIs were modified into only four patterns (evenly, breakfast dominant, lunch dominant, and dinner dominant) all of them except the evenly distributed pattern were linked to lower cognitive function. However, none of them were associated with an accelerated loss of function. 

Other studies have linked meal timing to improvement in short-term cognitive function, this study is in line with other research indicating that dividing energy intake into even meals helps to improve short-term cognitive function. Previous research suggests that meal timing can have an effect on our circadian clock which resides in two clusters of nerve cells called the suprachiasmatic nuclei located in the anterior hypothalamus near the base of our brains. 

“We have two different kinds of internal clocks (circadian rhythm). One is located in the brain (central clock or central circadian clock), and the other clock in some peripheral tissues, including fat, liver, intestine, and retina (peripheral circadian clock). While the central clock is mainly regulated by light, the peripheral clock can be regulated by multiple factors, including central clock and feeding,” explains Dr. Hoon-Ki Sung, Ph.D., associate professor in the Department of Laboratory Medicine & Pathobiology at the University of Toronto.

Sung suggests that circadian nutrition may relate “to a circadian rhythm diet or circadian diet.” Meaning that “you are keeping the feeding rhythms synchronized with your internal clock.” He noted that eating this way can include three meals, “as well as meal [or] energy intake between meal times.”

In Western society, three meals a day stemmed from the Industrial Revolution out of the needs of employers and workers. Before this,  two large meals a day were more common which was based off of household and farming duties. It just makes sense to eat a meal before the time of day that you will be the most busy, for some that will be in the morning, and this is why breakfast is often advised, which is especially true for school-aged children.