ultra processed foods. lecture 21

nutrition in health and disease

what is a processed food ?

(slides): USDA defines as a food that has undergone any changes to its natural state – that is, any raw agricultural commodity subjected to washing, cleaning, milling, cutting, chopping, heating, pasteurizing, blanching, cooking, canning, freezing, drying, dehydrating, mixing, packaging, or other procedures that alter the food from its natural state. The food may include the addition of other ingredients such as preservative, flavors, nutrients, and other food additives or substances approved for use in food products, such as salt, sugars, and fats. The Institute of Food Technologists includes additional processing terms like storing, filtering, fermenting, extracting, concentrating, microwaving, and packaging

even if you wash grapes, you are still consuming a minimum (washed off microbomes) (?) might ask lerman about this

breaking and chopping could create chemical composition changes (yes)

food processing has happened a thousands of years ago - crops were preserved for winter seasons -

“whether carried out within households, artisanal settings, or factories, food processing aims to ensure product safety, digestibility, and palatability”

why does it matter ?

• proponents of classifying and studying processed foods hypothesize that foods altered by some kinds of processing may have different relationships with health outcomes compared to unadulterated forms

• they believe traditional systems (food groups, for ex) misclassify foods, mixing “healthy” and “unhealthy” foods in the same category

• also, processed foods are ubiquitous (present, found everywhere) in the american food supply

food processing is essential in

producing affordable foods

producing affordable foods

• the food industry is a critical component in decreasing food costs

• buy materials in large quantities

• use energy efficient processing steps

• maximize yield to decrease waste

• utilize food waste products to offset processing costs

• utilize food processing operations, packaging technologies and food ingredients to maximize shelf life

• example: modify oxygen in packaged salad with mixed greens

just for reference:

homemade tomato paste = $9.90 +/ poumd

industrial tomato paste = $2.00 / pound

additional benefits of industrial food processing

more sustainable

• less energy

• one of the major cost of food production

• continous operation

• minimal need for preheating and cooling

• less cleaning = less water

• better timing and temperature control

• less overcooking which can destroy nutrients and produce toxins

additional benefits of industrial food processing

more effective utilization and preservation of nutrients

• can increase nutrient bioavailability

• milling, masa, increase bioavailability of fat soluble nutrients

• fortification to deliver essential nutrients to broad spectrums of the population

• process foods shortly after harvest to lock in nutrient’s

• less nutrient degradation compared to home cooking

• ultrapastuerization - 135 c for 2-5 seconds

• high temp kills bacteria quickly

• short processing time minimizes vitamin destruction

unwanted consequence of food processing / cooking

• vitamin degradation (gets lost in processing)

• processing can form unwanted by-products

-acrylamide

has been controlled by decreasing arginine in raw material, ex: potato chips

-Heterocyclic amines and advanced glycation products

can be minimized by controlling cooking temperatures and inhibiting browning

-Nitrosamines

can be minimized by controlling cooking temperatures and minimizing residual nitrites

-Bezene

can be controlling by not using benzoic acid as a preservative

• many of these compounds are also formed by home cooking

-no strong evidence that they are worse in industrially processed foods

there are a lot of nutrient benefits to processing foods

while it’s negative, it also has positives

just to have an idea:

graph representing why we might relate to health

purple boxes on the far most left side= many contributions

bottom 2 blue boxes= long shelf lives, additives and packaging materials could be a problem

ultra processed food consumption among US adults from 2001-2018

in class: not vastly different in the last 20 years. Slight increase.

check other graphs in slides too

orange dots = earlier

black dots= later dates

energy intake increasing from categories (most things going up)

sugar sweetened beverages → going down ) but other things are going up

a complication

• no agreed upon way to define this

• there is not a universal definition for classification of degree of food processing

• at least 3 systems have been suggested and used, and the most popular has multiple versions

• include the UNC, IFIC, and the NOVA

• NOVA= classify “all foods according to the nature, extent, and purposes of the industrial processes they undergo”

look at different categories on slides

Nova food processing classification system

• group 1 unprocessed or min processed foods (not processed or min processed. ex= grapes)

• group 2 processed culinary ingredients (ingredients in food: oils or added salts)

• group 3 processed foods (processed in some way: some degree of fermentation. ex: pickling)

• group 4 ultra processed foods (doesn’t have intact foods from 1st group. ex=frozen pizza, soft serve, ice cream)

group 1

processing includes removal of inedible / unwanted parts. does not add substances to the original food

group 2

substances derived from group 1 foods or from nature by processes include pressing, refining, grinding, milling, and drying

group 3

processing of foods from group 1 or 2 with the addition of oil, salt, or sugar by means of canning, pickling, smoking, curing, and fermentation

group 4

formulations made from a series of processes including extraction and chemical modification. includes very little intact group 1 foods

ambiguity of the UPF classification

Braesco et al. >150 nutrition and food science experts, medical doctors, and dietitians evaluated and classified 120 marketed foods (19,080 assignments) and 111 generic foods (19,647 assignments). Even though the evaluators had intermediate to high confidence in their assignments, only 3 marketed foods and 1 generic food were assigned to the same Nova group by all the evaluators, and most of the foods in both lists were placed in 2, 3, or even 4 different Nova groups by different evaluators (40). Thus, the level of misclassification, even among nutrition and food scientists, is unacceptably high, and these results severely undermine the validity of all the UPF concept and the observational studies on UPF and health outcomes

research roadmap

• we can’t figure out what they ate and how processed it was

• that’s a lot of questions to ask

• example=burger- don’t know what kind of burger

instead of asking what did you eat and following them over time, he put them on an ultra processed diet. fed people UPF only for 2 weeks and 2 weeks on clean / unprocessed deit.

• significant difference in calories

• people gained weight (ultraprocessed diet)

next steps with UPF

• can’t define them well, but we think intake is increasing and harmful

• do we start banning UPF or advising against it, even if we don’t know the real culprit and can’t tell a consumer exactly how to identify them ?