For years, a vegetarian diet has been considered one of the healthiest for humans. Now, a new study has found that eating a high-quality diet rich in plant-based foods is associated with a reduced risk of dementia, even when people begin following it in their late 50s and 60s.
A large study published in the journal Neurology and including about 93,000 participants with an average age of 59 found that a high-quality plant-based diet is associated with a 7%–12% reduction in the risk of dementia. In contrast, a low-quality plant-based diet that includes refined grains, fruit juices, potatoes and added sugars was associated with an increase of about 6% in risk.
It is important to emphasize: This is not a vegetarian or vegan diet, but a plant-based diet, meaning a combination of more plant foods, and not necessarily avoiding animal-based foods.
The study defined “healthy” plant foods, including whole grains, fruits, vegetables, legumes, nuts, plant-based oils, tea and coffee, compared with “less healthy” plant foods such as refined grains, juices and sugars. In addition, consumption of animal foods such as meat, dairy products, eggs and fish was also taken into account.
The interesting part of the study showed that a long-term shift toward an unhealthy plant-based diet increased the risk of dementia by about 25%, while improving diet quality reduced the risk by about 11%.
“The findings reinforce a broad research trend in recent years, but also clarify a critical point that can sometimes be missed in the discourse,” says Luda Nevo, a clinical dietitian at Maccabi Healthcare Services.
“The study found that a plant-based diet, even without considering food quality, reduces the risk of dementia. However, there are differences between a low-quality plant-based diet and a high-quality plant-based diet. While a high-quality plant-based diet is associated with a 7%–12% reduction in dementia risk, a low-quality plant-based diet that includes refined grains, fruit juices, potatoes and added sugars was associated with an increase of about 6% in risk.
Nevo explains that “there is no contradiction. The very shift toward a diet richer in plant foods may reduce risk, but within the plant-based world itself, quality is what determines it. In other words, it is possible to reduce dementia risk through a plant-based diet rich in legumes, whole grains, vegetables and healthy fats, but a plant-based diet based on processed foods may even increase risk.”
According to her, the differences between high-quality and low-quality plant-based diets are dramatic: “There is a big difference between a menu based on legumes, whole grains, vegetables and healthy fats, and a menu based on white flour pastries, ‘vegan’ snacks and juices. Both are ‘plant-based’, but their impact is completely different.”
The study clearly shows that it is not enough to ‘eat plant-based’ – it is also important to pay attention to the type and quality of food. A plant-based diet can be very healthy, but it can also become a diet high in sugar, white flour and processed foods, and in such a case it is no longer protective, and may even be harmful.
One of the important messages from the study is that even in the late 50s and 60s, the age when the risk of dementia increases, it is not too late to make a dietary change, and it has a real impact on dementia risk. This is a very encouraging message for the public.
Nevo concludes that “in practical terms, the main recommendation is to focus on improving diet quality, with a shift toward a plant-based diet but with a strong emphasis on food quality.”
Here are some everyday examples
- Instead of sweetened breakfast cereals, even if they seem healthy, prefer homemade granola or oats
- Instead of orange juice or sugary drinks, eat a whole fruit and switch to drinking green tea, which is rich in polyphenols that also have a protective effect
- Instead of white bread, choose whole wheat or rye bread, or combine legumes such as chickpeas, lentils and quinoa
- Instead of processed “healthy” snacks, combine nuts or almonds with a date
- Instead of store-bought sauce or spread, use spreads such as tahini or avocado
In the end, a high-quality plant-based diet not only contributes to brain health, but is also associated with a reduced risk of other chronic diseases such as diabetes and heart disease, and therefore this is a nutritional approach with very broad value for lifelong health