Dementia, a broad term for memory loss, trouble problem-solving, muted thinking abilities, and limited social skills, is a diagnosis no one wants to hear. It leads to less independence later in life, and can make people feel isolated and depressed. More than 7 million people in the US suffer from it, and women are slightly more likely to have it than men. Finding ways to prevent dementia is therefore increasingly important.
Causes of Dementia
What causes dementia in the first place? In general, it starts with damage to brain cells. (That damage takes time to accumulate, which is why most people first see symptoms in their mid 60s.) Different types of cell damage are linked to different types of dementia. For instance: Alzheimer's disease, the most common kind of dementia, occurs when certain proteins collect inside and outside brain cells, making it hard for them to communicate. Parkinson's disease, a progressive disorder that harms the central nervous system and makes it difficult to control movement, occurs when certain nerve cells that produce dopamine die or become damaged. (Dopamine is not just the "happy hormone" — it also helps control and coordinate body movements.)
What, then, causes brain cell damage that leads to dementia? For most patients, it's a combination of factors, from genetics to lifestyle. While you can't control every factor, there are a few steps you can take now to support prevention later — starting with your diet. Below are four foods that are linked to an increased risk of dementia.
1. Red Meat
It's not likely that the occasional burger or salami slice will cause dementia, but you may want to reconsider eating red meat on the regular. A 2019 study published in the BMJ found that the more red meat study participants ate, the greater their risk of death from dementia. The study authors theorized that high concentrations of saturated fat and trans fat in the blood — plus low concentrations of unsaturated fat — could cause dysfunction in the blood-brain barrier. (The blood brain barrier is a border of cells that prevents certain particles in blood from crossing into the brain.)
A 2021 study published in the American Journal of Clinical Nutrition had slightly different findings. In this study, researchers found that higher intakes of processed meat correlated with a higher risk of dementia. Unprocessed red meat, on the other hand, correlated with a lower risk.
A grain of salt: These studies were observational — the researchers for both studies used data from medical records and surveys. This means the researchers can't prove that eating red meat causes dementia, because they had no control over the participants' diets or lifestyle. (In the 2021 study, for instance, participants who ate processed red meat were more likely to smoke and exercise less.)
According to the UK Alzheimer's Society, drinking alcohol in excess has well-documented negative effects on brain health. In both the short and long term, it can cause brain damage that may lead to dementia.
Why is alcohol harmful to brain health? Scientists are not yet sure whether it has a direct, toxic effect on brain cells or whether the nutritional problems it creates are the true culprit. Heavy alcohol use can deplete levels of thiamine, or vitamin B1. Very low levels of thiamine may cause chronic memory issues.
Does this mean you have to give up all alcohol? Not necessarily; the research on moderate drinking is inconclusive. However, even the upper limit — about five large glasses of wine a week — can have negative effects on your health. So, an occasional glass of red is okay, but try to avoid making it a habit.
3. Refined Grains
In a 2020 study published in the Alzheimer's & Dementia journal, researchers found that a higher intake of refined grains — think white bread, cake, and crackers — in the afternoon correlated with an increased dementia risk. Why? The study authors theorized that the afternoon is when people snack between meals. Those snacks are often high carb, low protein, and low fiber, a recipe for a blood sugar spike. Regularly snacking on refined grains between meals could increase insulin resistance and body inflammation overtime, two factors that raise a person's risk of dementia.
In a 2017 study from Clinical Nutrition, researchers found that a diet high in refined grains (along with processed meats and sweets) tends to create low-grade, systemic inflammation in the body. That constant inflammation correlates with faster cognitive decline.
4. Excess Sugar
As with processed grain, eating too much sugar is linked to cognitive decline. A 2013 study published in The New England Journal of Medicine found that high blood sugar levels may increase the risk of dementia. Additional research shows that too much sugar can cause the brain to shrink and lead to small-vessel disease, which curbs blood flow to the brain.
Why does high blood sugar increase inflammation? Some scientists theorize that it raises the risk of vascular conditions, such as atherosclerosis (hardening of arteries) and heart disease. Others think that insulin resistance is the true problem, because it impairs brain signals. Still others think it's a combination of both.
The Bottom Line
We know what you're thinking — it's time to go cold turkey on red meats, alcohol, and processed foods. However, cutting all of these foods out of your life entirely may be unrealistic, especially with the holidays coming up. Our advice: Try filling your meals with healthy ingredients like leafy greens, whole grains, and lean protein first. This gives you less room to fill up on processed stuff. If you're unsure of wear to start, speak with your primary care physician or a nutritionist.
This content is not a substitute for professional medical advice or diagnosis. Always consult your physician before pursuing any treatment plan.