The study was conducted by the Online Center for Biomedical Research in the Physiology of Obesity and Nutrition (CIBEROBN) and the Human Nutrition Unit of the University of Rovira i Virgili-Instituto Sanitària Pere Virgili in Tarragona, Spain. It was part of the PREDIMED-Plus project framework and resulted from the collaboration of scientists from the Associated Online Center for Biomedical Research in Epidemiology and Public Health and the Online Center for Biomedical Research on Diabetes and Metabolic Diseases.
said Jiaki Ni, a pre-doctoral researcher at CIBEROBN and first author of the study Medscape Spanish Edition That this work was done due to the increasing prevalence of cognitive impairment worldwide, including dementia. This increasing prevalence is an increasingly important public health problem. “To this day, there are still no effective treatments available to treat cognitive disorders or slow the rate of impairment to this level. Therefore, prevention strategies that target modifiable risk factors, such as dietary intake and eating habits, remain a promising approach.”
Regarding the research hypothesis, Ni commented, “On the one hand, previous studies have indicated that consumption of milk and other types of dairy products plays a beneficial role in preventing age-related cognitive impairment and dementia. However, the evidence is somewhat controversial and unclear, especially When looking at consumption over time.”
Similarly, the “type of dairy products according to their fat content or the state of fermentation in which the dairy is present” was not always clear in the previous research, which was the reason for the current study.
The study included 4,668 participants in the PREDIMED-Plus study between the ages of 55 and 75 years. Participants were overweight or obese and had metabolic syndrome, which was defined as having at least three of the following five criteria: altered blood glucose level, elevated triglyceride levels, high blood pressure, abdominal obesity, and low levels of protein-cholesterol High density lipid. Participants completed a validated food frequency questionnaire at study baseline and a broad range of neuropsychological tests at study baseline and after two years of follow-up.
The saturated fat hypothesis
“The results showed a positive association between higher consumption of whole milk and the rate of cognitive impairment in older adults at risk of cardiovascular disease compared to those who consumed less milk during the two-year follow-up period. Most whole milk showed cognitive impairment. However, No significant association was observed between consumption of low-fat milk and dairy products or with fermented (yogurt, cheese) or non-fermented (all types of milk) dairy products.”
The biological mechanism by which whole dairy products have this negative effect on cognitive function is unclear. One possibility that researchers are studying relates to the effect of saturated fats (whole milk is rich in this type of fat) on cardiovascular risk factors, such as obesity, type 2 diabetes, high blood pressure, and dyslipidemia.
“These factors have been associated with an increased risk of cognitive impairment associated with pathological changes in the blood vessels. Saturated fats have been suggested to increase low-density lipoprotein cholesterol, which negatively affects blood lipids and increases the risk of atherosclerosis and other cardiovascular diseases,” Ni .
“Although saturated fat is one of the nutrients in dairy products that has been suggested to affect cognition, it has been suggested that the effects of these fats should be taken into account in the context of the overall source of calories consumed and dietary pattern. However, she added, ” More studies are needed to confirm this speculation.”
Nayara Fernandez, PhD, a nutrition expert and leadership group member of the Spanish Society of Geriatrics and Gerontology, who was not involved in the research, told Medscape that the benefit of eating dairy in Alzheimer’s disease has previously been linked to its ability to develop Alzheimer’s disease. Inhibit inflammatory cytokines, reduce oxidative stress, and inhibit beta-amyloid deposition.
Fernandez added: “Similarly, the intake of dairy products has been associated with the prevention of cardiovascular events, as it is a protective factor for independently causing arterial hypertension and diabetes. These are all risk factors for the development of cognitive impairment.”
“With regard to the specific role of whole milk, based on the population in which an association was seen, with a high vascular risk, it appears to be correct to link intake of milk fat, especially saturated fat content, with cognitive loss especially considering that this association It is not preserved if semi-skimmed or semi-skimmed dairy products are ingested.”
Another evidence provided by this investigation is that the negative effect on the cognitive level of whole milk consumption is more pronounced in men than in women.
“In fact, we saw in our results that total milk consumption was associated with cognitive impairment, at two years of follow-up, in men, but not in women. Different physiological features of these two groups could be associated with this outcome, as well as anthropometric and lifestyle factors (smoking) physical activity and adherence to the Mediterranean diet) and various disease prevalence present at the start of the study, but more research is needed in this regard,” said Ni.
With regard to the possibility of extrapolating these findings to an older population in general without risk of cardiovascular disease, in Ni’s opinion, the observational design of the study makes it not possible to establish causation. “Because a specific population was analyzed with these particular traits, these results could not be extrapolated to the general population, nor could it be determined that the presence of a cardiovascular risk profile was critical to these findings. However, this study allows us to provide evidence for further research on this the topic “.
Fernandez also urged caution when relaying these findings to the elderly and, above all, avoiding generalization. “Older people, in the context of physiological aging, and because of the comorbidity they usually develop, may have specific nutritional requirements, are more likely to develop malnutrition and, secondly, sarcopenia, which puts their functional independence at medium-term risk,” she said. A comprehensive assessment of the elderly to analyze their needs and to develop an individualized intervention plan, in which goals are set, as well as in terms of prevention of cognitive decline, is the way forward for elderly people with or without proven vascular risks. ”
Personal nutritional advice
Regarding nutritional guidelines in general, and those referring to the consumption of dairy products in particular, that target this population group, Fernandez noted that consuming three servings of dairy products per day (in the form of milk or dairy equivalent units) Derivatives: Yogurt, cheese, etc) is recommended. She noted the need to ensure adequate supplies of calcium and vitamin D to ensure healthy bones and muscles.
Similarly, Fernandez commented on other evidence, in line with this investigation, linking certain nutrients to cognitive health. “There are several studies that have linked alcohol intake to the development of dementia directly through degeneration or indirectly due to the appearance of vascular events that, in the long run, lead to the development of cognitive impairment. Likewise, intake of products with a high index of Blood sugar (simple sugars and white bread) also predisposes to a loss of cognitive function, even in people without diabetes.
“On the other hand, the scientific evidence linking dietary salt content to cardiovascular, brain and blood vessel health, as well as neurodegenerative diseases, is extensive, so we must limit its use to ensure a healthy lifestyle. Likewise, reducing intake of products high in is known to Saturated fats enhance cognitive function over the years.”
Fernandez emphasized that to ensure that muscular and cognitive function is preserved in the elderly, it is necessary to conduct an individual nutritional assessment, explore individuals’ cooking habits and consider their financial capacity. Within this framework, the main general recommendations are to avoid consumption of alcohol, reduce salt intake, and products rich in saturated fats and with a high glycemic index, for which the use of low-fat (skimmed or semi-skimmed) dairy products should be considered. Shimmed) in the event of a high vascular risk.”
Ni stressed that cognitive impairment is a long-term process. “Therefore, it will be interesting to continue this study, especially as we complete 6 years of the PREDIMED-Plus project intervention, to study the associations of dairy consumption and change in cognitive function in the 6 years after that—even, with the research focusing on the importance of clinical evidence.”
Nee and Fernandez reported no relevant financial conflict of interest.
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This article was translated from the Spanish edition of Medscape.
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