Can fish help protect our brains as we age?

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Could eating fish protect against cerebrovascular disease? luoman/Getty Images
  • Cerebrovascular disease – or cerebral vascular disease – which affects the blood vessels of the brain, is the fifth leading cause of death in the United States.
  • Health experts link fish consumption to a lower risk of cerebrovascular disease and the accompanying decline in cognitive function.
  • A recent cross-sectional study found a link between higher fish consumption and lower levels of markers of vascular brain injury in healthy older people, particularly those aged 65 to 74.
  • The effect of fish consumption two to three times a week on brain markers associated with cerebrovascular disease was of a similar magnitude to the effect of high blood pressure, which was associated with increased brain vascular damage.

Cerebrovascular disease, or vascular brain disease, refers to multiple conditions that affect blood vessels and blood flow in the brain, such as strokes and vascular malformations.

Cerebrovascular disease is the second number one cause of death worldwide. It is also the fifth leading cause of death in the United States and was responsible for 37.6 deaths per 100,000 people in the United States in 2017.

In addition to causing physical disability, cerebrovascular disease can lead to the development and progression of cognitive impairment and dementia.

Additionally, health experts also link subclinical cerebrovascular damage — that is, brain abnormalities seen in the early stages of cerebrovascular disease before its symptoms become evident — with an increased risk of dementia.

Healthy lifestyle modifications, including dietary changes, increasing physical activity levels and quitting smoking, can reduce the risk of cerebrovascular disease.

For example, there is a relationship between higher fish consumption and a lower risk of stroke. Fish is an excellent source of omega-3 polyunsaturated fatty acids, which may contribute to these cerebrovascular health benefits.

However, evidence that fish consumption reduces vascular brain damage before the onset of cerebrovascular disease is mixed.

A recent cross-sectional study investigated the link between fish consumption and cerebrovascular injury in healthy older adults before the onset of cerebrovascular disease.

The study reports an association between eating fish two or more times per week and lower levels of brain abnormalities linked to cerebrovascular injury, particularly in people younger than 75.

The study’s lead author, Dr Cecilia Samieri, a senior researcher at the University of Bordeaux in France, explains: “Our results are exciting because they show that something as simple as eating two or more servings of fish per week is associated with less brain damage. and other markers of vascular brain damage, long before the onset of obvious signs of dementia. However, eating so much fish did not have a protective effect in people aged 75 and over.

The study appears in the journal Neurology.

This study analyzed data collected between March 1999 and March 2001 as part of the Three-City Study, which aims to understand the relationship between vascular disease and dementia in people aged 65 and over.

The analysis focused on 1,623 people with an average age of 72.3 years and residing in Dijon, France. People were excluded from the study if they had a diagnosis of dementia, a history of stroke, or hospitalization for cardiovascular disease.

The researchers assessed the extent of subclinical cerebrovascular damage using brain MRIs.

They analyzed MRI scans for the presence of three markers associated with subclinical cerebrovascular lesions:

White matter is made up of nerve fibers, or axons, which relay messages between regions of the brain. Cerebrovascular disease can cause nerve fiber degeneration and damage the myelin sheath that surrounds nerve fibers. This leads to white matter abnormalities.

Infarctions are areas of dead tissue resulting from insufficient blood supply. This is often due to a blood clot in a blood vessel.

Perivascular spaces are fluid-filled spaces surrounding blood vessels. When enlarged, they are associated with small vessel brain disease.

Each of these markers predicts the extent of cognitive decline related to cerebrovascular disease. However, previous studies have shown that a single measurement obtained by combining multiple markers of cerebrovascular disease may be a better predictor of cognitive decline than any single marker.

Scientists refer to a combined measure of several cerebrovascular disease markers as the global burden of cerebrovascular disease.

At baseline, the researchers assessed the participants’ weekly intake of various foods, including meat, fish, fruits and vegetables, legumes and grains, using a brief questionnaire.

They assessed the relationship between the global burden of cerebrovascular disease and the frequency of fish consumption. They noted a link between a higher frequency of fish consumption and lower levels of cerebrovascular disease markers.

Participants consuming fish two or more times per week had lower combined levels of cerebrovascular disease markers than those who ate fish less frequently.

Additionally, the strength of the association between lower levels of cerebrovascular disease markers and frequency of fish consumption was influenced by age. This association was strongest in younger participants aged 65 to 69, but was not statistically significant in people older than 75.

The researchers observed similar results after adjusting for several variables, such as age, gender, physical activity levels, education levels, brain size and food consumption.

Health experts associate high blood pressure with an increased risk of cerebrovascular disease. The authors of the present study observed a similar association between levels of cerebrovascular disease markers and high blood pressure, regardless of the age of the participants.

To further contextualize the results, the researchers compared the impact of high blood pressure on markers of cerebrovascular disease with the frequency of fish consumption.

In participants aged 65 to 69, eating fish twice a week had a similar effect on levels of cerebrovascular disease markers like high blood pressure, but in the opposite direction.

Additionally, the magnitude of the effect of eating fish four or more times per week on levels of markers of vascular brain damage was twice that of high blood pressure.

Dr. Jyrki Virtanen, associate professor at the University of Eastern Finland, who was not involved in the study, spoke with Medical News Today.

He said: “This is an interesting and potentially important study, as it has shown that eating fish can benefit the brain and that benefits can be detected even before signs appear. or manifest symptoms.”

“The magnitude of the association was also quite large, as it was roughly similar to hypertension (a major risk factor for cerebrovascular disease), but in the opposite direction.”

– Dr. Jyrki Virtanen

“An interesting finding was also that the beneficial association was mainly seen in younger participants,” he explained. “This may mean that to reap the brain health benefits of eating fish, you need to eat fish regularly at a younger age.”

Highlights of the study include the use of high-resolution MRI to assess three different markers and derive a more comprehensive measure of overall cerebrovascular health.

The researchers also analyzed the data after controlling for many variables, such as lifestyle choices, education level, age, etc., which could have impacted the analysis.

There were, however, some limitations to the study. Dr Virtanen noted: “A major limitation of the study is that it is a cross-sectional observational study, so it cannot establish a causal link between fish consumption and better brain health, c that is, higher fish consumption leads to better brain health.”

“However,” he continued, “in nutrition research, well-conducted observational studies can provide good evidence for diet-disease relationships.”

The authors also note that they administered the food frequency questionnaire only once during the study and that the survey may not represent long-term eating habits.

Magda Gamba, a nutritionist and doctoral student at the Institute for Social and Preventive Medicine at the University of Bern in Switzerland, who was not involved in the study, said DTM:

“This is an observational study associating fish consumption measured at a given time with image indicators of cardiovascular disease burden. This means that we cannot draw direct conclusions about fish as a food that prevents brain damage.

“Further studies are warranted in order to truly establish whether fish is the true determinant of the MRI marker results observed in this study,” Gamba concluded.

“Further research is needed to help us understand the mechanism by which fish consumption may preserve brain vascular health,” says lead author Dr. Samieri, “because diet is a factor that people can modify to possibly reduce their risk of cognitive decline and even dementia later in life.”

Gamba also noted, “This article contributes to knowledge of the relationship between fish consumption and brain health; young adults seem to benefit more, but in general, a healthy diet as part of a healthy lifestyle is recommended for all people to keep the brain healthy and functioning, regardless of age.

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