Eating plenty of nuts, seeds and vegetable oils may reduce the risk of being sent to an early grave, scientists say.
Iranian researchers reviewed dozens of studies spanning up to three decades on diets and death rates.
They looked specifically at the effects of alpha-linolenic acid (ALA) – an omega-3 found in plants such as soybeans and flaxseed.
The results showed that people with a high intake of the nutrient – about 1.6 g per day – were 10 percent less likely to die from any cause, compared with those who consumed the lowest amounts – about 0.7 g .
Deaths from heart disease were also lower in people who ate a diet rich in nuts and other foods rich in ALA.
For every 1 gram increase in ALA per day — about a tablespoon of canola oil — the risk of dying from cardiovascular disease decreased by five percent, the study claimed.
However, the review also found that consuming large amounts of ALA was linked with an increased risk of dying from cancer.
The study, published in the British medical journal, states that further trials are needed to confirm the link.
Cardiovascular disease – the world’s leading cause of death – is responsible for 160,000 deaths a year in the UK and 659,000 in the US.
Alpha-linolenic acid – an omega-3 found in plants such as soybeans, nuts and flaxseed – was found to reduce the risk of overall mortality, as well as the risk of dying from cardiovascular disease
The graphs show how alpha-linolenic acid (ALA) – an omega-3 found in plants such as soybeans, nuts and flaxseed – intake affects the risk of all-cause death (top left), cardiovascular disease (top right), coronary heart disease (bottom left) and cancer (bottom right). A high intake of ALA was associated with a 10 percent decrease in the risk of death, an 11 percent decrease in the risk of dying from coronary heart disease, and an eight percent decrease in the risk of dying from cardiovascular disease. However, the findings suggest that the seeds may be associated with a slight increase in cancer risk, but warned that more studies would be needed to confirm this.
Previous studies have shown that ALA is associated with a lower risk of fatal coronary heart disease – a type of cardiovascular disease.
But a slew of others were inconclusive about whether the nutrient improved mortality.
To address the uncertainty, the team at Tehran University of Medical Sciences analyzed the results of 41 studies published between 1991 and 2021.
A total of 1.2 million adults – mostly from Western countries – participated in the studies, which were followed between the ages of two and 32.
About 198,113 deaths were recorded, of which 62,773 were due to cardiovascular disease, while 65,954 were due to cancer.
The study found that adults who ate a lot of ALA-rich foods were 10 percent less likely to die from all causes — equivalent to 113 fewer deaths per 10,000 person-years.
And it reduced the odds of dying from cardiovascular disease by eight percent — which would lead to about 33 fewer deaths per 10,000 person-years.
Sina Naghshi and colleagues also saw the more ALA a person consumed, the less likely they were to die of cardiovascular disease.
There were 63 additional cancer deaths per 10,000 person-years among those who ate the highest amounts of omega-3, compared to those who ate the least.
The review was observational, so cannot conclude that ALA consumption certainly fueled improvements or cancer risk.
But researchers believe their findings are “robust” and boast that they add to “evidence of the potential health benefits of polyunsaturated fatty acids.”
Experts believe that ALA helps heart health by lowering cholesterol and improving blood pressure.
They said further studies should examine the link between ALA and other causes of death to determine whether it could be linked to reducing the risk of death from other causes.
Experts should also look at specific ALA-rich foods to see if the way the omega-3 is consumed affects death rates.
They warned that recommendations to eat more ALA should be made “with caution” because of their discovery of a possible link with cancer.
WHAT SHOULD A BALANCED DIET LOOK LIKE?
Meals should be based on potatoes, bread, rice, pasta or other starchy carbohydrates, ideally whole grains, according to the NHS
• Eat at least 5 servings of different fruits and vegetables every day. All fresh, frozen, dried and canned fruits and vegetables count
• Basic meals on potatoes, bread, rice, pasta or other starchy carbohydrates, preferably whole grain
• 30 grams of fiber per day: This is equivalent to eating all of the following: 5 servings of fruits and vegetables, 2 whole-grain cereal biscuits, 2 thick slices of whole-wheat bread, and large baked potato with skin
• Have some dairy or dairy alternatives (such as soy drinks) and choose options with less fat and less sugar
• Eat some beans, legumes, fish, eggs, meat and other proteins (including 2 servings of fish per week, one of which is fatty)
• Choose unsaturated oils and spreads and consume in small amounts
• Drink 6-8 cups/glasses of water a day
• Adults should have less than 6 g of salt and 20 g of saturated fat for women or 30 g for men per day
Source: NHS Eatwell Guide