If you eat a high-protein diet, you might want to put down your knife and fork. According to a study published last week in Cell Metabolism, following a protein-packed diet may increase your risk of early death.
After tracking 6,381 adults aged 50 and over for 18 years, the researchers found people who ate a high-protein diet (at least 20 per cent calories from protein) during middle age had a 74-per-cent increased risk of overall mortality and were four times as likely to die from cancer than their low-protein (less than 10 per cent protein calories) counterparts. They were also more susceptible to dying from diabetes.
The results showed that protein from animal sources (meat, dairy, eggs) accounted for much of the link between protein and early death. The findings also hinted that a diet based on plant proteins (beans, lentils, nuts, soy) was protective.
The researchers speculate that a high intake of animal protein increases levels of insulin and IGF-1, a growth hormone that's been linked to cancer development.
This isn't the first time that what you eat has been linked to longevity. Studies have documented that people who follow Mediterranean and vegetarian diets have longer life expectancies. Your diet may slow aging in a number of ways. Antioxidants like vitamins C and E, lutein and beta-carotene fend off harmful free radicals, unstable oxygen molecules that damage cells and contribute to aging. Omega-3 fatty acids, monounsaturated fat and flavonoids dampen inflammation, a contributor to numerous chronic diseases.
A diet based on low-glycemic carbohydrates, including oats, quinoa, sweet potatoes and legumes, helps maintain healthy blood glucose and insulin levels. Monounsaturated fats may also benefit insulin levels and blood-sugar control.
Certain nutrients also help preserve the length to telomeres, sequences of DNA that protect the ends of chromosomes from damage. Telomere shortening – which happens every time a cell divides – has been linked to aging, cancer and a higher risk of dying.
The B vitamins folate, B6 and B12 are needed to help prevent an amino acid called homocysteine from rising in the bloodstream; elevated homocysteine is implicated in heart disease, stroke and dementia.
Research suggests the following 10 nutrient-packed foods have the potential to slow aging in cells and promote longevity.
They're packed with anti-inflammatory monounsaturated fats – just like olive oil – along with plenty of folate, a nutrient that helps repair DNA and rids the body of homocysteine.
Add avocado to salads, soups and tacos; spread mashed avocado on whole-grain bread instead of butter or mayonnaise.
These root vegetables are loaded with cancer-fighting anthocyanins and are a good source of folate. Beets also contain betaine, a B vitamin-like compound shown to reduce inflammation and homocysteine.
Add grated raw beets to salads and sandwiches; roast beets along with other winter vegetables; sauté cooked beets with a grated orange rind and a splash of orange juice.
A diet high in fibre – especially from cereal grains – is associated with a lower risk of cardiovascular death. Fibre-rich cereals help keep blood cholesterol and blood pressure in check and improve insulin action.
Mix 1/2 cup of 100-per-cent bran cereal with your favourite breakfast cereal; add 1/4 cup bran to a smoothie; sprinkle bran cereal over fruit salad and yogurt.
High in fibre and vitamin C, blackberries are also packed with anthyocanins.
Stir blackberries into yogurt, blend them in a smoothie or add a handful to breakfast cereal; toss into a spinach salad; mix blackberries into muffin and pancake batters.
This cruciferous vegetable is packed with glucosinolates, phytochemicals that mop up free radicals and help the liver detoxify carcinogens. You'll get more anti-cancer benefits if you eat cabbage raw or lightly cooked.
Add shredded cabbage to salads, soups, wraps and fish tacos; include cabbage in stir-fries; make a homemade coleslaw with shredded carrot and fresh dill.
They're high in plant protein and fibre, not to mention an outstanding source of folate – one half-cup delivers nearly half a day's worth.
Add lentils to pasta sauce instead of ground meat; toss cooked lentils into green salad; stir lentils into soups and stews.
The juicy seeds of this fruit are an excellent source of potent antioxidants called polyphenols. They're also a source of fibre, folate and vitamin C.
Add pomegranate seeds to fruit and green salads, sprinkle over oatmeal, blend in smoothies, stir into yogurt and mix into muffin and pancake batters; top roasted vegetables with pomegranate seeds.
It's an excellent source of alpha-carotene, a phytochemical shown to block the growth of cancer cells. Research suggests higher blood levels of the compound guard against death from cancer and cardiovascular disease.
Add pure pumpkin purée to smoothies, muffin, loaf and pancake batters; make a homemade soup with pumpkin purée, orange juice and curry power. (Pumpkin purée is sold in cans; unlike pumpkin pie filling it has no added sugar, fat or spices.)
As one of the best sources of omega-3 fats, salmon may protect from heart disease, Alzheimer's and macular degeneration. Higher blood levels of omega-3's (the type in fish) are also related to a slower rate of telomere shortening.
Add cooked salmon to an egg-white omelette; top a spinach salad with canned salmon as a change from tuna.
This leafy green delivers when it comes to lutein (for eye health) and vitamin K (for strong bones). Like lentils, spinach is also an exceptional source of folate.
Add spinach leaves to pasta sauces, soups and omelets; use spinach instead of lettuce in sandwiches; serve steamed spinach with a splash of raspberry vinegar.
Leslie Beck, a registered dietitian, is based at the Medisys clinic in Toronto. She can be seen every Thursday at noon on CTV News Channel's Direct (lesliebeck.com).