Nutrition is an exciting and ever-changing science. As our understanding of nutrients and food constituents, their metabolism and impact on risk of chronic disease improves, our evidence-based dietary recommendations change. What we thought was good, bad or indifferent 10 years ago may prove to be something else entirely in the future, which results in a revolving-door of nutrition recommendations and rumours – it is no wonder consumers are left baffled!
A recent survey in the US found that 76% of people reported conflicting and changing nutritional guidance as a major barrier to improving their food habits. Whether because the message is not getting out, or in the case of calcium supplements and CVD the WRONG message is getting out, consumers are often confused and discouraged.
Here’s our countdown of some of the “oops” moments and missteps in nutrition over the last few decades – areas where misconceptions and confusion still abound. Let’s set the evidence-based record straight!
The culprits in Part 1 include: eggs, low-fat foods, soy and antioxidant supplements. This is not the end of the list though, stayed tuned for the final four next week.
- Eggs. The poor egg! Maligned as a terrible-for-you food for so long and still a source of confusion. I regularly have clients who continue to avoid eggs at all costs (or consume those questionable egg-free liquids) out of concern for their cholesterol levels.
No Baloney’s advice. Eggs are not bad for you; in fact, they contain nutrients not commonly found in other foods. Keep cooking method in mind – a fried bacon, egg and cheese sandwich doesn’t count. See our previous post on The Yolk – A Burden or Blessing? for more on eggs and health.
- Low-fat = weight loss. We definitely learned our lesson after the low-fat and fat-free craze of the ‘80s and ‘90s… or did we? Fat-free products continue to spill off of the shelves in grocery stores, despite new evidence indicating that they may be doing more harm to our waistline than good. Sadly, noses still turn up at good-for-you foods that are rich in healthy fats, like almonds, avocado and even fish, because of their calorie content, even though an abundance of evidence supports their role in weight maintenance. Doesn’t seem the message has gotten out that chowing down on processed, low-calorie foods doesn’t equate to weight loss.
No Baloney’s advice. Eat real food and focus on healthy fat, not no fat! Fat in food serves several purposes, one of which is to promote satiety (how long you feel full after a meal). This is exactly why that 30 calorie fat-free, sugar-free yogurt leaves you hungry within minutes – it’s barely food! See our previous post Low Calorie – Weight Gain? for links to the low-calorie research.
- Soy and breast cancer. For years women with breast cancer were told they should avoid all foods containing phytoestrogens, including tofu, soy milk and flaxseed. Now a growing body of evidence has dismissed this guidance as outdated and unnecessary (1). Dietitians and doctors encouraged women with estrogen-receptor positive (ER+) breast cancer to avoid soy and flax out of concern for increased risk of cancer recurrence with these estrogen-mimicking foods. Not only did this create a fear of foods and eating, it flew in the face of some groups’ recommendations to follow a more flexitarian diet with less meat and research linking soy products to reduced risk of cancer. Importantly, nutrition recommendations are not the same for everyone. A recommendation for a patient with a specific form of breast cancer should not be applied to the population as a whole.
No Baloney’s advice. Phytoestrogen-containing products are safe for those with and without breast cancer to consume, though current recommendations suggest limiting to two servings per day in those with ER+ breast cancer, taking care to avoid all soy supplements. For more information, we like BC Cancer Agency’s Nutrition Guide for Women with Breast Cancer.
- Antioxidant supplements improve health. Remember when vitamin E supplements were recommended for everyone with heart disease? Thankfully, this practice has gone of the way of the dodo since vitamin E supplements were first linked with increased risk of all-cause mortality (2). But this isn’t the first time we’ve gotten it horribly wrong when it comes to supplements and health. First, it was shown that beta-carotene not only didn’t decrease risk of lung cancer in smokers, it actually increased risk (3). Then the SELECT trial involving selenium and vitamin E supplementation for the prevention of prostate cancer was discontinued because the vitamin E supplement groups were linked to increased prostate cancer incidence (4). More recently, new evidence suggests associations between vitamin A, beta-carotene, folate, vitamin E and selenium supplements and cancer risk, particularly in high doses (5,6).
No Baloney’s advice. Look at all of your supplements and compare to the tolerable upper intake levels – you should not exceed these levels for any micronutrient unless advised by your doctor. But staying below the UL does not guarantee safety, as vitamin E supplements demonstrate.
Think about why you take your supplements – are they actually necessary? What evidence is their proposed efficacy based on? Are there any safety concerns? We suggest going to food first, particularly antioxidant-rich plant foods like veggies, fruit, nuts and seeds. See our previous post on Antioxidant Supplements: Helpful or Harmful? for information on supplements and performance.
There are so many more nutrition controversies we couldn’t fit them all on one list! Check back next week for the final four on our list. We hope our myth busting has helped. Feel free to suggest others in the comments!
- Nechuta SJ, et al. Soy food intake after diagnosis of breast cancer and survival: an in-depth analysis of combined evidence from cohort studies of US and Chinese women. Am J Clin Nutr 2012 [epub ahead of print].
- Miller ER 3rd, et al.Meta-analysis: high-dosage vitamin E supplementation may increase all-cause mortality. Ann Intern Med 2005; 142:37-46.
- Omenn GS, et al. Risk factors for lung cancer and for intervention effects in CARET, the Beta-Carotene and Retinol Efficacy Trial. J Natl Cancer Inst 1996; 88(21):1550-9.
- Klein EA, et al. Vitamin E and the risk of prostate cancer: the Selenium and Vitamin E Cancer Prevention Trial (SELECT). JAMA 2011; 306:1549-56.
- Martínez ME, Jacobs ET, Baron JA, Marshall JR, Byers T. Dietary supplements and cancer prevention: balancing potential benefits against proven harms. J Natl Cancer Inst 2012; 104:732-9.
- Fox JT, et al. High-throughput genotoxicity assay identifies antioxidants as inducers of DNA damage response and cell death. Proc Natl Acad Sci USA 2012; 109:5423-8.