Opinion by Katerina Stylianou and Olivier Jolliet
Updated: Thu, 23 Sep 2021 15:42:26 GMT
Editor's Note: Katerina Stylianou is a research associate at the University of Michigan School of Public Health and the director of public health information and data strategy at the Detroit Health Department. Olivier Jolliet is professor in environmental health sciences at the University of Michigan School of Public Health. The opinions expressed in this commentary are their own. View more opinion articles on CNN.
When our nutrition study came out last month, headlines around the world focused on the finding that eating a single hot dog can take 36 minutes off your life expectancy due to the presence of processed meat and sodium, which increase the risk of ischemic heart disease and diabetes. There was less emphasis on the good news in the study: Eating a serving of peanuts or peanut butter, for example, could add 25 minutes since nuts reduce the risk of ischemic heart disease and diabetes -- and therefore increase the probability of a healthier life.
Overall, making minor targeted dietary changes could make a big difference both for health and the environment.
Americans dedicate 1.7 hours or about 100 minutes per day on average for food preparation and cleanup, eating and drinking. The choices that we make during this time can affect our health as well as our planet.
As the interconnectedness of diet, health and environment is becoming clearer, many people are wondering how to eat healthier, how their food is grown and sourced and how to minimize their impact on the environment. These concerns are added to the long list of factors that influence dietary choices such as taste, budget, culture, food availability, preexisting health conditions -- and, yes, a pandemic.
Food labels are meant to communicate health and, more recently, environmental information to consumers to help them make more informed choices. However, current food labels are either hard to understand, require additional knowledge to interpret and typically only focus on either the nutrition, health, or environmental performance of the food items. So, how can we use up-to-date scientific information to make healthy and sustainable food choices easier?
We decided to evaluate the health and environmental performance of individual foods, with the help of Victor Fulgoni, an expert in nutrition. His for-profit company, Nutrition Impact, LLC., provided food profiles that allowed us to create the Health Nutritional Index (HENI), which measures the number of healthy minutes of life gained or lost per serving of food. Healthy minutes refers to living a disease-free live -- gains and losses of healthy minutes are linked to the decreased or increased risk-probability of developing a disease or early death.
HENI takes into account 15 dietary factors from the Global Burden of Disease, which studies the burden of disability and death from a number of causes. These cover health benefits associated with food containing milk, nuts and seeds, fruits, calcium, omega-3 fatty acids from seafood, fibers and polyunsaturated fatty acids (PUFAs) and health damages associated with food containing processed meat, red meat, trans fatty acids, sugar-sweetened beverages and sodium. For each of these dietary factors, we estimated the healthy minutes of life lost or gained per gram of food consumed.
For example, we found that a person eating a gram of sodium in the US is losing 7.4 minutes primarily due to the increased risk of developing ischemic heart disease and other cardiovascular diseases. This means that for a serving of chicken wings containing about 0.5 grams of sodium you can lose an average of 3.6 minutes from sodium alone.
Taking into consideration other components of chicken wings such as polyunsaturated fatty acids (0.6 minutes gained), calcium (less than 0.1 minutes gained), and trans-fatty acids (0.3 minutes lost) results in an overall net of 3.3 minutes of healthy life lost.
We studied environmental performance, which was based on 18 indicators, including carbon footprint, water footprint and air pollution. Using these methods, we evaluated 5,853 foods and we found that there are ways to minimally change your diet that will greatly improve your health and reduce environmental impact ... without requiring drastic lifestyle changes like going vegan.
Our study, which was published in Nature Food and funded by an unrestricted grant from the National Dairy Council and the University of Michigan Dow Sustainability Fellowship, found a large range of health benefits and risks across food items. What's more, we found variability in the performances of similar foods due to the large number of diverse recipes.
For example, the HENI scores for seafood range from about 10 minutes of healthy life lost to 70 minutes of healthy life gained. This difference is largely driven by the omega-3 fatty acid content found in each seafood that can reduce the probability of ischemic heart disease.
The scores for breakfast sandwiches range from 1 to 34 minutes lost due to the diversity of ingredients and their quantities in each sandwich; sandwiches high in lunch meat shave more minutes of healthy life than meatless sandwiches that are typically higher in vegetables.
On the environmental side, a serving size of beef steak produces about 3.8 kg CO2 equivalent in greenhouse gas emissions, twice more than pork roast and lamb (both at 1.5 kg CO2 equivalent), 6 to 13 times more than milk, about 9 times more than poultry, and between 13 and up to 50 times more than nut-based products such as salted peanuts.
We compared both the nutritional and environmental impact of each food to identify in a traffic lights analogy: "green foods" that are beneficial for health and have low carbon footprint, "red foods" that are the worst for health and for the environment, and intermediary amber foods that have moderate impacts.
Based on this, we developed simplified recommendations for foods that should be increasingly consumed, foods that should be decreased in your diet or avoided, and foods to eat in moderation. Additionally, we looked at the question of whether dramatic dietary changes are needed to live a healthier and more sustainable life. In short, we wanted to help answer the question: Should we all go vegan to save the planet and live a healthier life? The answer, we found, is: not necessarily.
Our study showed that small targeted dietary changes yield substantial gains for human health and environmental sustainability. Overall, replacing on a daily basis 10% of caloric intake from beef and processed meats with whole grains, fruits, vegetables, nuts, and sustainably sourced seafood could reduce your dietary carbon footprint by 30% and add 48 healthy minutes per day.
The best strategy we found is to reduce or possibly eliminate the "red foods" that are the worst for health and/or for the environment. For health, these are processed meat and sugar-sweetened beverages; for the environment, these are beef, followed by pork and lamb.
We can replace them with less damaging but somewhat similar foods, such as poultry or dairy products, or, even better, replace them with foods linked with low carbon emissions and health benefits, such as field-grown fruits, vegetables, whole grains and sustainably sourced seafood.
The beauty here is that, based on their performance of nearly 6,000 foods, we identified a plethora of items that are beneficial to health and friendlier on the environment. And there are numerous food options that can improve one's diet without a large impact on budget, culture and taste. The best use of our findings is to develop personalized and diversified diets that are made of foods with the highest beneficial health impacts per calorie and the lowest environmental impact per calorie.
However, it is important to highlight that while environmental impacts are additive (the more eco-friendly food choices we make, the bigger the positive impact we can have on the environment), nutritional health scores are not.
This means that we can identify better food choices but even if we only eat the healthiest foods, we cannot live forever. For example, the benefits from consuming nuts and fruits are capped once we reach 20.5 grams of nuts per day or 250 grams of fruit per day, respectively.
So, the health nutritional index is there to help you make the most potent change within your own life. It is also there to help governments, food banks and schools to subsidize and prioritize healthy and sustainable foods.
While our study shouldn't be interpreted to mean that you should not eat another hot dog as long as you live, it can teach us how, by making small changes to our diets, we can obtain a maximum benefit for our health and the environment ... one food item at a time!