How ultra-processed foods increase your dementia risk

From instant noodles to soft drinks, UPFs set people up for chronic diseases, experts say

What we put on our plates does far more than fuel our bodies – it affects our heart health, inflammation levels, hormone regulation, blood pressure, sleep quality and mood.

Each of these elements is a major risk factor for dementia. Dr Helen Macpherson, an associate professor at Deakin University’s faculty of health in Australia, rates diet an 8.5 out of 10 in terms of its importance for long-term brain health.

“Diet has a direct effect on the brain in terms of the nutrients we supply it with,” Macpherson says, noting that a poor diet also acts as an indirect driver of chronic conditions that slowly erode cognitive function.

While most of us can easily identify a healthy meal – one packed with fruits, vegetables, whole grains, nuts and seeds – fewer realise how well a toxic diet can masquerade as a nutritious one. From yogurts packed with hidden sugars to fitness bars loaded with preservatives, dietary appearances can be deceptive.

Macpherson uses the Nova scale to identify hidden hazards. It categorises food based on the extent of industrial processing, from unprocessed or minimally processed foods to ultraprocessed food – industrial formulations made mostly or entirely from food-derived chemicals and additives. Biscuits and instant noodles are examples.

According to Michael Greger, an American doctor and author of the books How Not to Die and How Not to Age, identifying ultra-processed foods (UPFs) is usually straightforward.

“Basically, anything sold in a bag or a box is a UPF.”

Food manufacturers frequently modify even staples widely perceived as healthy. Most packaged breads rely heavily on artificial additives, colourings, emulsifiers and dough conditioners to extend shelf life and improve texture.

Greger maintains that cumulative chemical exposures may have toxic effects on the body.

A similar marketing contradiction applies to diet yogurts. While low-sugar options are frequently promoted as health-conscious alternatives to regular yogurt, they are often made with artificial sweeteners.

A high UPF diet will set people up for a range of noncommunicable chronic diseases HELEN MACPHERSON, DEAKIN UNIVERSITY

This shift towards factory-made food has completely changed how we eat.

Chemical formulations and novel ingredients – to which the human body has no historical exposure – now make up close to 60 per cent of the average American adult’s diet, and a worrying 70 per cent of what their children consume.

It is the impact on children that worries Macpherson most.

“They may be in store for a lifetime of calorie-dense, nutrient-sparse food,” she warns, noting that this shift will inevitably spike rates of type 2 diabetes and drastically reduce their overall healthspan.

A high UPF diet will set people up for a range of non-communicable, chronic diseases, all of which increase the risk of developing dementia” later in life, she adds.

While local diets in Hong Kong may still outshine those in the US, UPFs are a growing concern. Recent surveys highlight a high consumption of processed meats and salty, packaged snacks

The consequences of this dietary shift are already visible.

Just a generation or two ago, type 2 diabetes was exceptionally rare in Hong Kong, affecting roughly 1 per cent of the population. Today, it is common. Recent data suggests that as many as one in 10 local adults now suffer from diabetes or elevated blood sugar.

This is a red flag for cognitive health, especially given that many researchers now refer to Alzheimer’s disease as “type 3 diabetes”.

The greatest threat UPFs pose to the brain, though, may stem from what they do to the heart. Consuming excess trans fats, saturated fats and cholesterol raises blood cholesterol levels.

According to Greger, this is a primary driver not just of heart disease, but of Alzheimer’s.

“It all starts with atherosclerosis – the hardening of the arteries,” Greger says, referring to when fatty, cholesterol-rich plaques build up inside the blood vessels.

When the arteries leading to and inside the brain become clogged, it drastically restricts blood flow and deprives it of vital oxygen. “Because the ageing brain is highly sensitive to a lack of oxygen, poor blood flow may lead to cognitive decline,” Greger says.

“Autopsies have shown that Alzheimer’s patients had particularly significant arterial blockage in the arteries leading to the memory centres of their brains.”

Safeguarding long-term brain health, it seems, does not begin with a puzzle or a brain-training app.

It starts on our plates.