Health impact of processed foods – good or bad?
Processed foods have recently hit the headlines with links to health concerns and diet quality, but are the reports right , and what exactly IS a processed food?...
Definitions of processed foods vary significantly; some are highly sophisticated (eg LanguaL or the Foodex classifications) and others are broader and more simplistic (such as NOVA classification). As recently reported, processed foods can contribute up to 50% of our shopping baskets so what are their impact on our health?
First stop – the definition of processed. The broader definitions group together processed meats, confectionery, wholegrain bread and wholegrain breakfast cereals all in the same category. One key measure missing from these type of definitions is the energy density and nutrient content – after all, how can health impacts be assessed without understanding the calories and nutritional make up which are key drivers of energy intake and health?
So second stop – nutrition quality…
Higher energy density foods can increase calorie intake through passive overconsumption. Processing foods can result in the addition of fats and sugars which can increase calories, however it isn’t an automated road to higher energy density. Processing has resulted in the development of lower fat dairy products (eg semi-skimmed milk, low fat yogurts), low fat spreads and calorie controlled meals which help to reduce total calories as well as saturated fat, sugars and salt.
A review by Gibney et al (2017) on the impact of processed food on human health suggested ‘Food reformulation and processing has given rise to a variety of products which vary in energy density and calorie content’.
An increased inclusion of vegetables and pulses has been made possible through processing in a range of products (such as prepared meals, meat products, sandwiches, breads and chilled snacks) which naturally lowers energy and saturated fat content whilst helping to boost 5 a day – a public health commitment we are still struggling to meet (NDNS 2016).
A significant proportion of vitamins and minerals are sourced from processed and enriched foods – especially folic acid, calcium, vitamins A and D; many nutrients which we struggle to obtain enough of from the diet yet have important roles in our health. The EPIC study (Slimani 2009) showed processed foods contributed between 50-90% of dietary sources of these nutrients particularly from breads, breakfast cereals, pasta sauces and low fat spreads.
The recent interest in plant based diets and reducing dairy has required the role of processing to enrich alternatives with nutrients usually found in milk (calcium, B vitamins and iodine), some of which we have limited other dietary sources (iodine).
Processing has also led to improvements in nutritional profile such as:
- Increases in wholegrain and fibre content (especially in breads, breakfast cereals, white carbohydrates and prepared meals)
- Boosting fruit, veg and pulses content – to increase fibre, plant proteins and reduce calories and saturated fat.
- Reformulating to reduce calories, total fat, saturated fat, sugar, salt
- Milling of grains – which decreases heavy metals in the tough outer layers to increase availability of minerals
- Increasing nutrient bioavailability through cooking – eg tomatoes (lycopene), eggs (biotin), carrots (beta carotene)
One of the biggest hurdles of following a healthy diet is time – we have less time to plan, prepare and make healthy food and snacks. As a result, we’re eating more food on the go, out of home.
Processing can make key components of healthy diets more accessible and easier to include more frequently. Gone are the days of pre-soaking wholegrains and pulses, instead they’re available in ready to eat pouches or pots and incorporated in salads, snacks, breads and cereals. Providing important sources of fibre (soluble and insoluble), protein, B vitamins, zinc and selenium.
Processed food also tend to be labelled with clear visibility of recommended portion size, calories and nutritional break down made to strict weight controls and measures. This can be especially valuable to those who are managing calories who often struggle utilising visual and sensory cues to estimate appropriate portion size and calorie content.
So the verdict…
Processed foods in their broad context are difficult to attribute to primary health outcomes without being overlayed with energy density, nutrient quantity and impact on meal patterns as these have significant impacts on the quality of our diets. They have been shown to have a role to play in micronutrient content and improving accessibility and availability to important food groups in the diet, especially as we continue to eat more food on the go and away from home. Perhaps calorie capped portion size is the key processing approach for the future that can help customers manage their calories and nutrient intake from typically indulgent foods that are sometimes the hardest to manage.
Gibney M, Forde C, Mullally D et al (2017) Ultra-processed foods in human health: a critical appraisal. American Journal of Clinical Nutrition. 106(3). 717-724.
Slimani N, Deharveng G, Southgate D et al (2009) Contribution of industrially processed foods to the nutrient intakes and patterns of middle-aged populations in the European Prospective Investigation into Cancer and Nutrition study. European Journal of Clinical Nutrition. 63 (4). S206-225
Bates B, Cox L, Page S et al (2016) National Diet and Nutrition Survey. Results from Years 5-6 (combined) of the Rolling Programme (2012/13-2013/14). London. Public Health England