Medical Bulletin 08/ May/ 2024

A recent study published in the journal Neurobiology of Aging determined whether a high-fat diet contributes to memory decline in older people compared to aging alone.

Increased consumption of highly processed foods, which are rich in calories but poor in nutrients, has contributed to rising rates of obesity and related diseases like high blood pressure and type 2 diabetes mellitus. These conditions are risk factors for cardiovascular disease (CVD) and cancer.

Obesity is also linked to cognitive dysfunction, including anxiety, depression, memory decline, and impaired learning. Neuroinflammation, a consequence of obesity, further exacerbates cognitive impairment and neurodegeneration.

High-fat diets can induce inflammatory neuronal damage within a week of exposure, leading to dysregulated feeding and weight gain. Additionally, these diets can trigger hippocampal inflammation, resulting in memory deficits.

In the study, female rats were fed a high-fat and high-sucrose diet (HFSD) for eight weeks, and their brain microglia and inflammatory markers were examined. Rats consuming HFSD showed accelerated weight gain compared to those on a regular diet, with aged rats gaining weight faster than young rats.

Both groups also had increased fat mass, while lean mass decreased in relation to fat mass. Aging was linked to higher microglia expression in the brain, particularly in the hypothalamus and hippocampus, with no further increase when rats were fed HFSD. Recognition memory declined with both aging and high-sucrose diet consumption, but high-sucrose diet did not exacerbate the effect of aging.

The findings suggested that aging and HFSD may affect rat behavior by causing cognitive deficits and anxiety, even when microglia are depleted. This indicated that microglia may not be the direct cause of cognitive dysfunction observed with aging and HFSD in the short term.

“These results indicate a potential disconnect between the peripheral pro-inflammatory response caused by HFSD and the central pro-inflammatory, or at least, primed, profile seen in aging. Our data suggest that mechanisms additional to the acute microglial contribution play a role in aging- and HFSD-associated memory dysfunction,” said the study authors.

Reference: Malik, S., Xavier, S., Soch, A., et al. (2024). High-fat diet and aging-associated memory impairments persist in the absence of microglia in female rats. Neurobiology of Aging. doi:10.1016/j.neurobiolaging.2024.04.010.

According to a study published in the journal JAMA Network Open, a higher intake of olive oil is associated with a lower risk of dementia-related mortality.

Olive oil, particularly extra virgin olive oil, is renowned for its health benefits, including its positive impact on brain health. Rich in monounsaturated fats like oleic acid and antioxidants such as polyphenols, olive oil helps protect brain cells from oxidative stress and inflammation, key factors in cognitive decline and neurodegenerative diseases like Alzheimer's.

Regular consumption of olive oil, as part of a Mediterranean diet rich in fruits, vegetables, fish, and nuts, has been associated with improved memory, cognitive function, and overall brain health. Its anti-inflammatory properties further contribute to maintaining brain health, making it a valuable component of a brain-boosting diet.

“A study published in 2022 used cohort data to show that higher olive oil intake was associated with a lower risk of cardiovascular disease, cancer, neurodegenerative disease, and respiratory disease mortality. Other studies like this meta-analysis, also published in 2022, show a lower risk of diabetes, [cardiovascular disease], and all-cause mortality from higher olive oil intake,” said Anne Danahy, a registered dietitian nutritionist.

In the study of 92,383 participants, mostly women with an average age of 56, researchers conducted a 28-year follow-up. At the study's outset, average olive oil consumption was 1.3 grams/day. Those consuming over 7 grams/day: Had higher calorie intake, but not higher BMI; Followed a better diet; consumed more alcohol; were more physically active and were less likely to smoke

The result concluded that consuming 7 grams of olive oil daily was linked to a 28% lower risk of dementia-related death. Substituting 5 grams/day of margarine and mayonnaise with olive oil showed an 8% to 14% lower risk. They also concluded that higher olive oil intake was associated with reduced dementia-related mortality, regardless of diet quality, expanding dietary recommendations for cognitive health.

“This is an observational study, so it doesn’t show a direct cause and effect. Olive oil is rich in vitamin E and polyphenols — antioxidants that protect cells and blood vessels, including those in the brain. It also has anti-inflammatory properties. Inflammation can accelerate aging in the brain (and body) and it’s thought to be an underlying cause of dementia and cognitive decline,” concluded Danahy.

Reference: Tessier A, Cortese M, Yuan C, et al. Consumption of Olive Oil and Diet Quality and Risk of Dementia-Related Death. JAMA Netw Open. 2024;7(5):e2410021. doi:10.1001/jamanetworkopen.2024.10021

A new study conducted at the Postgraduate Institute of Medical Education and Research (PGIMER) in Chandigarh revealed that around 44 percent of women diagnosed with cardiovascular disease (CVD) are obese.

Cardiovascular disease is a major health concern in India, responsible for a significant number of deaths each year. Risk factors of cardiovascular diseases mainly hypertension, diabetes, obesity, sedentary lifestyle and stress are much more common in India than in the Western countries. Heart disease is not exclusive to men, it also affects women and is the leading cause of death.

“Cardiovascular diseases (CVD) show high risk to people with obesity or who are overweight, people who follow a sedentary lifestyle, stress, hypertension and diabetes,” said Dr Neelam Dahiya, assistant professor, department of Cardiology, PGIMER, Chandigarh who conducted the study for over the past three years.

The study conducted on 200 women of Chandigarh, who visited the PGI for treatment of heart diseases and the women accompanying them from their families between 2018 and 2020 revealed that every second woman among them is a victim of obesity. Additionally, symptoms of serious heart related diseases were also found in 44% of them.

The study highlighted that risk factors for heart disease are more prevalent in women compared to men. Furthermore, women with heart disease experience poorer outcomes, with a 50% higher mortality rate among those displaying signs of heart disease. The long-term prognosis for women with heart disease is concerning due to these factors. Additionally, obesity rates are rising more rapidly among women than men, increasing the risk of various conditions including heart failure, blood clotting disorders, and diabetes.

As shown in various studies, Indian diet is not heart-healthy one, Indians consume more salt and sugar and less of vegetables and fruits.

Consumption of a healthy diet even in a hectic work schedule is important. A diet rich in fruits, vegetables, whole grains, lean proteins, and healthy fats can provide essential nutrients, antioxidants, and fiber that support heart health. These foods help regulate cholesterol levels, lower blood pressure, reduce inflammation, and maintain healthy weight, all of which are key factors in preventing cardiovascular diseases.

Reference: Postgraduate Institute of Medical Education and Research (PGIMER) Chandigarh