Research associates ultra-processed foods with nutrient imbalances and increased intake of potentially harmful additives.supersizer/iStockPhoto / Getty Images
The increase in ultraprocessed foods in diets worldwide represents a major new challenge for global public health, according to a three-part series published this month in the Lancet.
And it’s one that requires a co-ordinated and urgent effort to reduce the consumption of UPFs and promote healthier diets.
The Lancet series, authored by 43 international experts, examined the scientific evidence for the health harms of UPFs and recommended policy actions to reduce UPF production, marketing and consumption and expand access to fresh foods.
The authors also outlined strategies to address the power of the hugely profitable UPF industry, including a strong global response to protect policy-making from industry lobbying, the main barrier to effective government policy.
What are UPFs?
UPFs, characterized by the presence of additives that enhance the texture, flavour and appearance of foods, are hyperpalatable and aggressively marketed (especially to children), driving repeated consumption.
A wide range of foods are classified as ultraprocessed – soft drinks, packaged snacks, mass-produced breads and bakery goods, protein bars, ice cream, processed meats, pre-cooked/ready-to-heat meals (such as frozen dinners and pizza, chicken nuggets), margarine and many more.
Made from inexpensive industrial ingredients, UPFs make up 46 per cent of calories consumed in Canada and about 55 per cent of calories consumed in the U.S. and the U.K. Consumption is increasing quickly in lower-income countries.
Health effects of UPFs
The authors reviewed decades of data that indicate UPF dietary patterns are displacing long-established diets centred on whole and minimally processed foods, resulting in a decline in diet quality.
Scores of studies, including randomized controlled trials, have associated UPFs with nutrient imbalances, overeating, reduced intake of protective phytochemicals and an increased intake of potentially harmful additives as well as toxic contaminants from processing and packaging.
Studies have found that a UFP dietary pattern can lead to inflammation, elevated blood glucose, cholesterol and triglyceride levels, unfavourable microbiome alterations and liver dysfunction.
The hypothesis that a high intake of UPFs increases the risk of multiple chronic diseases was substantiated by more than 100 studies. The evidence found adverse health outcomes across nearly all organ systems.
Tackling the UPF challenge will take time and require sustained global action.
In the meantime, expect to see continued evidence for the harmful effects of UPFs.
UPFs tied to colorectal polyps in women under 50
Other researchers have studied ultraprocessed foods for potential ties to colorectal cancer in women.
The incidence of early-onset colorectal cancer (diagnosed before 50 years of age) is rising in parallel with increasing consumption of UPFs. An observational study, published Nov. 13 in JAMA Oncology, shed light on how a high UPF diet may increase the risk of early-onset colorectal cancer.
Researchers from Harvard University and Mass General Brigham set out to determine if UPF intake was related to the risk of developing adenoma polyps, potential precursors for early-onset colorectal cancer. (Emerging risk factors for early-onset colorectal cancer include a diet low in fibre and high in red and processed meats and added sugars.)
Adenoma polyps are considered precancerous as they have the potential to grow into cancer over time.
The study included 29,105 female participants from the Nurses’ Health Study II, who were followed for 24 years.
They received at least two colonoscopies before age 50. UPF intake was obtained from diet information collected every four years.
Participants with the highest UPF intake (10 servings a day) had a 45 per cent increased risk of developing early-onset colorectal adenoma polyps compared to those with the lowest intake (three servings per day).
Increased risk for colorectal polyps remained strong after accounting for other risk factors including age, body mass index, history of Type 2 diabetes, smoking status, physical activity and diet quality.
The study did not find a cause-and-effect relationship; instead it uncovered an association between UPFs and colorectal polyps. The researchers also noted that UPFs do not fully explain the rise in early-onset colorectal cancer.
Protective dietary patterns
Hyperinsulinemia and chronic inflammation are two important and related biological pathways for chronic disease. Hyperinsulinemia occurs when your blood insulin levels are higher than what’s considered normal.
Not surprisingly, dietary patterns that lower inflammation and prevent excessive insulin spikes are associated with a lower risk of many chronic diseases, including heart disease, stroke, Type 2 diabetes and certain cancers.
These healthy eating patterns emphasize vegetables, whole fruit, whole grains, nuts, fish and dairy, especially fermented dairy such as yogurt, kefir and cheese, while limiting red and processed meat and added sugars. And they’re lacking ultraprocessed foods.
If your goal is to reduce your intake of ultraprocessed foods, make a list of the ones you eat on a regular basis. Are there some that you can make at home – perhaps salad dressing, hummus or granola?
Instead of processed deli meat, consider roasting a turkey breast for sandwiches and salads.
Replace highly processed snacks with whole and minimally processed ones such as kale chips, popcorn, whole fruit, unsweetened dried fruit, nuts, seeds and plain yogurt.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan.