Does Whole Milk Speed Cognitive Decline in Older Population?


Madrid, Spain. Evidence suggests that dairy consumption is associated with improved cognitive health in older adults. However, the results of a recent investigation introduce an exception to this possible connection. The researchers found that high consumption of whole milk was associated with higher levels of cognitive impairment in older adults at high risk for cardiovascular disease.

The study was conducted by the Online Center for Biomedical Research in Physiopathology of Obesity and Nutrition (CIBEROBN) and the Department of Human Nutrition of the University of Rovira y Virgili-Pere Virgili Institute of Sanitary Research in Tarragona, Spain. It was part of the PREDIMED-Plus project and was the result of a collaboration between scientists from the Associated Online Biomedical Research Center for Epidemiology and Public Health and the Online Biomedical Research Center for Diabetes and Metabolic Diseases.

Giaki Ni, a CIBEROBN researcher and first author of the study, told the Spanish publication Medscape that this work was carried out due to the increasing prevalence of cognitive impairment worldwide, including dementia. This growing prevalence is becoming an increasingly important public health issue. “To this day, there are still no effective treatments for cognitive impairment or slowing the rate of deterioration to this level. Therefore, prevention strategies that target modifiable risk factors such as diet and eating habits remain a promising approach.”


Regarding the research hypothesis, Nee commented that “on the one hand, previous studies have shown that consumption of milk and other types of dairy products plays a beneficial role in preventing age-related cognitive impairment and dementia. However, the data is somewhat conflicting. and unclear, especially when looking at consumption over time.”

Similarly, “the type of dairy products based on their fat content or the state of fermentation that those dairy products are in” was not always clear in previous studies, which was the reason for the current study.

The study included 4,668 participants in the PREDIMED-Plus study, aged 55 to 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, high triglycerides, high blood pressure, abdominal obesity, and low high-density lipoprotein cholesterol. Participants completed a validated meal frequency questionnaire at baseline and an extensive series of neuropsychological tests at baseline and 2 years of follow-up.


Saturated fat hypothesis

“The results showed a positive association between high consumption of whole milk and levels of cognitive impairment in older adults at high risk for cardiovascular disease compared with those who consumed less milk over a 2-year follow-up period. most whole milks showed cognitive impairment. However, there was no significant association between consumption of low-fat milk and dairy products, fermented (yogurt and cheese) or unfermented (all types of milk) dairy products,” Ni said.

The biological mechanism by which whole dairy products have such a negative impact on cognitive function is not clear. One possibility the researchers are considering is the effect of saturated fat (whole milk is rich in this type of fat) on risk factors for cardiovascular disease such as obesity, type 2 diabetes, hypertension and dyslipidemia.

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“These factors have been associated with an increased risk of cognitive dysfunction associated with pathological vascular changes. It has been suggested that saturated fat raises low-density lipoprotein cholesterol levels, which negatively affects blood lipids and increases the risk of atherosclerosis and other cardiovascular diseases. Neither.

“While saturated fat is one nutrient in dairy that has been suggested to affect cognitive function, it has been suggested that the effect of this fat should be considered in the context of overall calorie intake and dietary patterns. More research is needed to confirm these assumptions,” she added.

Naiara Fernández, Ph.D., a nutrition expert and member of the Steering Group of the Spanish Society of Geriatrics and Gerontology, who was not involved in the study, told Medscape that the benefits of eating dairy in Alzheimer’s disease have previously been linked to their ability to inhibit inflammatory cytokines, reduce oxidative stress, and prevent the deposition of beta-amyloid.


“Similarly, dairy consumption has been associated with the prevention of cardiovascular and cerebrovascular events, as they are a protective factor for the development of hypertension and diabetes independently. These are all risk factors for cognitive impairment,” Fernandez added.

“With regard to the specific role of whole milk, based on a population in which an association with high vascular risk has been seen, it seems appropriate to link milk fat intake, especially saturated fat content, with cognitive loss. function, especially given that this association does not persist in case of ingestion of semi-fat or low-fat dairy products,” she noted.

Gender differences

Another piece of evidence from this study is that the negative impact of whole milk consumption on cognitive levels is more evident in men than in women.


“Indeed, in our results, we saw that total milk consumption was associated with cognitive impairment at 2 years of follow-up in men, but not in women. The different physiological features of these two populations may be related to this result. as well as anthropometric, lifestyle factors (smoking, physical activity, adherence to a Mediterranean diet) and varying prevalences of diseases present at baseline, but more research is needed in this regard,” Ni said.

Regarding the possibility of extrapolating these results to the general older population without CV risk, Nee argues that the observational design of the study makes it impossible to determine causation. “Because a specific population with these specific characteristics was analyzed, these results cannot be extrapolated to the general population, nor can it be determined that the presence of a cardiovascular risk profile was decisive in these findings. However, this study allows us to provide evidence for further research on this topic.”

Fernandez also urged caution when transferring these findings to the elderly and, above all, avoid generalizations. “Older people, in the context of physiological aging and due to the comorbidities they commonly have, may have special nutritional needs, being at greater risk of developing malnutrition and secondarily sarcopenia, which puts their functional autonomy at medium-term risk. ,” she said. “Conducting a comprehensive geriatric assessment to analyze their needs and develop an individualized intervention plan that sets goals, including in terms of preventing cognitive decline, should be the way forward for older adults with and without established vascular risk . “

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Individual nutritional advice

With regard to dietary recommendations in general and recommendations for the consumption of dairy products in particular, intended for this population, Fernandez indicated that the consumption of three servings of dairy products per day (in the form of milk or equivalent units of its derivatives: yogurt, a serving of cheese, etc.) e) is recommended. She mentioned the need to make sure you get enough calcium and vitamin D to keep your bones and muscles healthy.

Similarly, Fernandez commented on other evidence that, according to this study, links certain nutrients to cognitive health. “There are numerous studies that link alcohol use to the development of dementia, either directly through degeneration or indirectly through the occurrence of vascular events that in the long term determine the establishment of cognitive impairment. the glycemic index (simple sugar, white bread) also predisposes to cognitive loss even in non-diabetics.

“On the other hand, the scientific evidence linking dietary salt with cardiovascular and cerebrovascular disease, as well as neurodegenerative diseases, is extensive, so we should limit its use to ensure a healthy lifestyle. Saturated fat is known to help maintain cognitive function over many years,” said Fernandez.

Fernandez emphasized that in order to guarantee the preservation of muscle and cognitive function in older people, it is necessary to conduct an individual assessment of nutrition, study people’s culinary habits and take into account their financial capabilities. “Within this framework, the main general recommendations are avoiding alcohol, limiting salt intake, foods rich in saturated fats and high glycemic index, which include consideration of the consumption of low-fat dairy products (low-fat or semi-fat). -fat-free) should be added in case of high vascular risk.

Nee stressed that cognitive impairment is a long-term process. “Thus, it would be interesting to continue this study, especially when we complete the 6-year intervention of the PREDIMED-Plus project, to study the associations of dairy consumption at that time and changes in cognitive function after 6 years. up by focusing research on the value of clinical data.”

Neither and Fernandez reported no relevant financial conflicts of interest.

Follow Carla Nieto of Spanish Medscape on Twitter @carlanmartinez.

This article was translated from the Spanish edition of Medscape.

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