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When evaluating foods, focus on nutrient content, not processing

February 9, 2022

by Dr. Mark Messina

A new analysis of data from a national survey to assess the health and nutritional status of adults (NHANES 2015-18) suggests that health attributes of soy-based burgers and soymilk should be based on nutrient content, not on the degree of processing used to make the foods.

Despite being a recently coined term that came into existence just more than a decade ago,  ultra-processed foods (UPFs) is one of the hottest topics in nutrition. Its popularity has come because of the advent of NOVA, a food classification system developed by Brazilian researchers.1 So far this year alone, more than 300 papers involving UPFs are indexed in PubMed.  This topic is very much relevant to the soy industry because most soymilks and the new generation of soy-based burgers are classified as UPFs. In spite of this classification, these foods can offer nutritional (e.g., high-quality protein)2,3 advantages. New research from a team of investigators indirectly highlights this point.4

The new generation of soy-based meats qualify as UPFs because they are typically made using concentrated sources of soy protein, such as soy protein isolate or soy protein concentrate, which are comprised of ≥90% and 65-90% protein, respectively.5 Even soymilks made from whole soybeans qualify because of the added sugar and emulsifiers they typically contain.6 The classification of these soy products as UPFs matters because UPF intake is associated with a host of adverse health outcomes.7 Consequently, dietary recommendations increasingly call for limiting the intake of these foods.

Proponents of the NOVA food classification system argue that independent of nutrient content, UPFs are unhealthful.8,9 This means that even if soy-based burgers and soymilk are nutritionally similar to their animal-based counterparts, hamburgers and cow’s milk, which are classified as unprocessed or minimally processed foods, the soy-based products are viewed by NOVA as less desirable from a health perspective. However, a new analysis of participants of NHANES 2015-18 suggests that any ill effects of UPF intake can be attributable to their impact on diet quality.4

The analysis involved 5,280 children and 9,758 adults. UPF intake was assessed using the NOVA food classification system and diet quality was determined according to the American Heart Association (AHA) primary and secondary score. The primary score is based on the intake of fruits/vegetables, whole grains, fish/shellfish, sugar sweetened beverages and sodium and the secondary score on those components plus the intake of nuts/seeds/legumes, processed meat, and saturated fat.

For children and adults, the cutoffs (percent kcal) for quintile 1 (reference, lowest intake) for UPF intake were <50.2% and <39.1%, respectively and for quintile 5, they were >79.0% and >70.7%, respectively. For both children and adults, there was a stepwise decrease in the AHA primary score (indicating poorer diet quality) when going from quintile 1 to quintile 5. Also, in quintile 1, 31.3% and 18.1% of children and adults consumed a poor-quality diet, respectively, whereas for quintile 5, those figures were 71.6% and 59.7%, respectively.  Poor-quality diet was defined as <40% adherence to the AHA secondary diet score.

Collectively, these data show that UPF intake is directly linked with the quality of the diet. Consequently, it is reasonable to conclude that the associations between UPF intake and adverse health outcomes observed in population studies are attributable to the quality of the diet, and not because there is something inherently non-nutritious about UPFs independent of nutrient content.

Therefore, when considering the health attributes of soy-based burgers and soymilk the focus should be on nutrient content, not on the extent to which a food classification system considers them processed.

References

  1. Monteiro CA. Nutrition and health. The issue is not food, nor nutrients, so much as processing. Public health nutrition 2009;12:729-31.
  2. Fanelli NS, Bailey HM, Thompson TW, Delmore R, Nair MN, Stein HH. Digestible indispensable amino acid score (DIAAS) is greater in animal-based burgers than in plant-based burgers if determined in pigs. Eur J Nutr 2021.
  3. Reynaud Y, Buffiere C, Cohade B, Vauris M, Liebermann K, Hafnaoui N, Lopez M, Souchon I, Dupont D, Remond D. True ileal amino acid digestibility and digestible indispensable amino acid scores (DIAASs) of plant-based protein foods. Food Chem 2020;338:128020.
  4. Liu J, Steele EM, Li Y, Karageorgou D, Micha R, Monteiro CA, Mozaffarian D. Consumption of ultraprocessed foods and diet quality among U.S. children and adults. Am J Prev Med 2021.
  5. Codex General Standard for Soy Protein Products, Codex Standard 175-1989. 1989.
  6. Drewnowski A. Perspective: Identifying ultra-processed plant-based milk alternatives in the USDA Branded Food Products Database. Adv Nutr 2021.
  7. Lane MM, Davis JA, Beattie S, Gomez-Donoso C, Loughman A, O’Neil A, Jacka F, Berk M, Page R, Marx W, et al. Ultraprocessed food and chronic noncommunicable diseases: A systematic review and meta-analysis of 43 observational studies. Obesity reviews : an official journal of the International Association for the Study of Obesity 2021;22:e13146.
  8. Small DM, DiFeliceantonio AG. Processed foods and food reward. Science 2019;363:346-7.
  9. Hall KD, Ayuketah A, Brychta R, Cai H, Cassimatis T, Chen KY, Chung ST, Costa E, Courville A, Darcey V, et al. Ultra-processed diets cause excess calorie intake and weight gain: An inpatient randomized controlled trial of ad libitum food intake. Cell Metab 2019;30:67-77 e3.

 This blog is sponsored by SNI Global and the United Soybean Board.