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On Oct. 17, registered dietitian Leslie Beck answered reader questions on the keys to healthy aging and how to manage a diet that can last decades. Beck, one of Canada’s leading nutritionists, is the clinical director of food and nutrition at Medcan and author of The Globe’s Food for Thought column.
Readers asked about which habits can improve cognitive health and longevity, the risks and benefits of certain food groups, and how best to maintain a healthy lifestyle. Here are some highlights from the Q&A.
Leslie Beck recommends people limit their consumption of foods sweetened with sugar alcohols, as well as artificial sweeteners.The Associated Press
What are the long-term benefits and risks of using sweeteners such as erythritol or xylitol?
Leslie Beck: Research published in 2023 and 2024 from the Cleveland Clinic Lerner Research Institute suggested that consuming either one of these sugar alcohols – erythritol or xylitol – could increase risk for cardiovascular disease.
The research found that erythritol and xylitol made it much easier for cells called platelets to clump together and form a blood clot. (Heightened blood clotting can increase the risk of heart attack and stroke.)
Keep in mind, though, the research findings are observational, meaning they do not prove that erythritol or xylitol directly causes blood clots. And these are preliminary studies, so more research is needed. Even so, I recommend people limit their consumption of foods sweetened with these sugar alcohols, as well as foods and drinks sweetened with artificial sweeteners.
Could lentils be considered vegetables?
Beck: No. Lentils are an excellent source of vegetarian protein, but they are not considered vegetables like broccoli and lettuce are. Lentils are a “pulse,” the dried edible seed of legumes. Chickpeas, kidney beans, pinto beans and black beans are pulses, too. Compared with vegetables, pulses have unique nutrient profiles. Besides protein, they are high in fibre, folate and magnesium, and contain many other essential nutrients. You can treat lentils as the main protein component of your meal or, if you’re having a lentil salad with chicken, you can treat it like the starchy food component. Either way, include non-starchy vegetables, too!
When deciding which oil to use, Beck says to consider how well it holds up to heat, its nutritional properties and the flavour it imparts to foods.CHRISTOPHER TESTANI/The New York Times News Service
Besides olive oil, what are some good options to use for cooking that are healthy choices?
Beck: I do recommend extra virgin olive oil as a nutritious and versatile cooking oil. It’s my go-to oil when sautéing or roasting vegetables (you can cook with it!), dressing salads and, sometimes, baking.
But it’s not the only bottle of cooking oil in my pantry. When deciding which oil to use, I consider how well it holds up to heat, its nutritional properties and the flavour it imparts to foods.
I also use a cooking oil that is a good source of vitamin E, an antioxidant that protects cells, especially brain cells, from damage caused by harmful free radicals. Adults need 15 mg of vitamin E each day. Top sources include sunflower oil (5.6 mg per tablespoon), safflower oil (4.6 mg per tablespoon) and grapeseed oil (4 mg per tablespoon). Olive, canola and peanut oils have 2 mg per tablespoon.
And one last word: Despite what you hear on social media about the harms of seed oils – canola, soybean, corn, sunflower, safflower and grapeseed oils – there is no evidence that they cause inflammation, heart disease or cancer. In fact, when these plant-based oils replace saturated fat in the diet, they’re associated with cardiovascular health benefits.
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Eggs and cholesterol, is there a final verdict or is it everything in moderation?
Beck: The debate over eggs revolves around their high cholesterol content (185 mg per one large egg, all in the yolk). For years, consuming too much cholesterol was thought to raise LDL (bad) blood cholesterol. Yet the consensus among scientists has been that cholesterol in food has little or no effect on most people’s blood cholesterol. Years ago, North American national dietary guidelines removed the daily cholesterol limit of 300 mg per day based on many studies finding there was no impact on risk of cardiovascular disease from eating up to one whole egg a day in healthy people without high blood cholesterol levels.
Two recent large reviews of observational studies have suggested that high intakes of whole eggs and of dietary cholesterol might be harmful and increase the risk of cardiovascular disease. In other words, a higher risk may only show up with higher intakes of cholesterol.
My advice: If you eat two or more eggs each day, consider cutting back to one egg per day. Make an omelette or scramble with one whole egg and egg whites. If you have high LDL cholesterol, existing heart disease or diabetes limit to four whole eggs per week.
Let’s not forget that eggs are nutritious. They’re an excellent source of protein, 42 per cent of which is found in the yolk. Eggs also deliver plenty of vitamin B12 (half a day’s worth in one large egg) and selenium, a mineral that protects DNA in cells and is needed for thyroid function. And egg yolks are the best food source of choline, a B-like vitamin that’s important for brain health; one large egg has 147 mg of choline. Women need 425 mg of choline each day; men need 550 mg.
Roasting nuts could increase the availability of certain beneficial compounds, Beck says.Drazen_/iStockPhoto / Getty Images
I am wondering if lightly toasting walnuts damages any of their nutritional benefits?
Beck: Roasting nuts – which I regularly do to enhance their flavour – does not diminish their nutritional value.
A 28 g serving of raw and dry roasted almonds, for instance, contain virtually identical calories (174 and 179, respectively) and the same amounts of protein, fibre, calcium, iron, magnesium, potassium, B vitamins and vitamin E. Roasting may even increase the availability of certain beneficial compounds such as flavonoids.
Research suggests that if you drink enough of it, coffee may protect your long-term health.Maryna Andriichenko/iStockPhoto / Getty Images
How does coffee fit into a healthy diet? I drink green tea occasionally.
Beck: Coffee definitely fits into a healthy diet! And the benefits of drinking coffee appear to go beyond its mental perks. Research suggests that if you drink enough of it, coffee may protect your long-term health. Plenty of evidence suggests that drinking three to five cups of coffee a day, and in some cases more, lowers the risk of many chronic diseases. (Researchers define a cup of coffee as six or eight ounces.)
Drinking coffee, regular or decaf, has consistently been found to protect against Type 2 diabetes. Drinking coffee has also been associated with protection from heart disease, gallstones, Parkinson’s disease, liver disease and certain cancers.
Heavy coffee drinking (six or more cups per day), however, has been tied to modest increase in heart disease risk.
Coffee contains protective phytochemicals, some of which have antioxidant and anti-inflammatory properties. Coffee also contains magnesium, a mineral that helps the body secrete and use insulin properly.
Green tea is very healthy, too. It’s high in anti-inflammatory polyphenols. The green-Mediterranean diet included 3 to 4 cups a day!
What food groups would you recommend to increase SCFAs (short chain fatty acids) and reduce inflammation in the GI tract and improve overall health?
Beck: When beneficial gut bacteria break down or ferment undigestible carbohydrates called prebiotics, short chain fatty acids are produced in the process. And that is a good thing since short chain fatty acids help strengthen the intestinal wall and reduce inflammation.
Prebiotic foods include asparagus, Jerusalem artichokes, jicama, leeks, onions, garlic, apples, bananas, kefir, whole-grain rye, barley, white kidney beans, chickpeas, soybeans and chicory root.
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What can you do if you have prediabetes to lower your risk of having diabetes?
Beck: By making diet and lifestyle changes now, you can prevent or delay prediabetes from progressing to diabetes. It is also possible to reverse prediabetes. Here some dietary and lifestyle recommendations:
Being overweight is the strongest risk factor for prediabetes and Type 2 diabetes. If carrying excess weight, losing a modest 5 to 7 per cent of weight can reduce the risk of developing diabetes.Consider the carbs you eat, and choose whole grains over refined grains as often as possible. Limit your intake of added sugars. Refined grains and added sugars cause rapid rises in glucose and insulin.Focus on carbs that have a low glycemic index. These foods cause slow and low rises in blood glucose and include things like beans and lentils, grainy breads, steel-cut oats, and sweet potato.Be active. Aerobic exercise, high intensity interval training and resistance training have been shown to improve insulin sensitivity in prediabetes.Open this photo in gallery:
Beck says that there is no scientific evidence to prove that eating nightshade vegetables, such as bell peppers, eggplants and potatoes, has a direct impact on arthritis symptoms.Dmitriy83/iStockPhoto / Getty Images
Is there any research or good anecdotal evidence that nightshade vegetables are inflammatory foods, particularly related to arthritis? Over time, do related food sensitivities drive chronic inflammation?
Beck: Nightshade vegetables (and fruits) include bell peppers, chili peppers, eggplant, tomatoes, tomatillos and potatoes. It’s often claimed that eating these foods can cause inflammation joint swelling, pain and stiffness.
The concern with nightshades revolves around alkaloids, naturally-occurring compounds in the leaves and stems that act as natural insect repellents. Alkaloids include solanine (found in potatoes, especially ones that have turned green), capsaicin (the chemical that gives chili peppers their heat) and nicotine.
The theory goes that alkaloids in nightshade vegetables promote inflammation and worsen symptoms in people with autoimmune inflammatory disorders such as rheumatoid arthritis, psoriasis and inflammatory bowel disease (e.g., ulcerative colitis, Crohn’s disease).
Yet, there is no scientific evidence to prove, or even strongly suggest, that eating nightshade vegetables has a direct impact on arthritis symptoms. The research is lacking.
As well, cooking further reduces the alkaloid content of nightshade vegetables.
Still, it is possible that some people are affected by nightshades. You might eliminate them from your diet for four weeks and then add them back and see how you feel.
Nightshade vegetables are very good sources of many anti-inflammatory nutrients and phytochemicals including vitamin C, beta-carotene, lycopene and anthocyanins.