Miniatura 6 for UPWr: resistant starch and senior nutrition

• Resistant starch is a component of dietary fibre, which stabilises blood glucose levels and is important in the prevention, among others, of diabetes. It is therefore important to find ways to obtain it without losing its properties
• The nutritional risk of seniors is becoming increasingly important - the Polish population is ageing, and nutrition is an important part of the prevention of civilisation diseases and, consequently, assessing the state of health of the elderly

Both projects are related to human nutrition in general and its impact on health and susceptibility to the development of civilisation diseases. Professor Małgorzata Kapelko-Żeberska from the Division of Carbohydrate Technology in the Faculty of Agricultural Technology and Storage already investigated ways of obtaining resistant starch, that is starch that is not digested and absorbed in the small intestine of a healthy person, in her doctoral thesis. The starch gets its name from its resistance to digestive enzymes, and is categorised as a component of insoluble dietary fibre. It is used as a filler in food products, and by participating in the complex mechanisms of digestion it stabilises blood glucose levels, which is of considerable importance in the prevention of metabolic syndrome, insulin resistance and type II diabetes. Dr. Robert Gajda has been involved with the nutritional risk of seniors for some time, including at the 1st National Scientific Conference 'Food and Nutrition in a Nutshell' held earlier this year, where he presented the nutritional risk differences among Polish seniors according to selected demographic characteristics and declared socio-economic status.

Both projects are to end by 30 September 2023.

A new approach to starch

Professor Małgorzata Kapelko-Żeberska's project will address the intensification of thermal re-polymerisation as a new method of obtaining resistant starch.  During these processes, non-starch-specific α-1,2 and α-1,3 glycosidic bonds may form, resulting in partial starch resistance to amylolysis.

– Most of my research work has been related to obtaining resistant starch by chemical modification. On the one hand, chemical processes are inevitable during food production, but on the other they have a potentially negative impact on food and therefore, in the long term, on human health. I therefore decided to focus on finding physical methods to modify starch in order to reduce its susceptibility to amylolysis - I shall be preparing starch with natural substrates using physical methods - says Prof. Małgorzata Kapelko-Żeberska, explaining that resistant starch is starch and its degradation products, which are not subject to enzymatic digestion and absorption in the gastrointestinal tract of a healthy person. Changing the structure of starch through physical and chemical modifications often reduces its susceptibility to amylolytic decomposition.

The starch available to the micro-organisms inhabiting the large intestine is of particular health-promoting importance, as it lowers the pH of the environment. The increased acidity of the intestinal contents is a result of the fermentation of resistant starch by microflora and the formation of short-chain fatty acids, which influence the selection of the colonising microflora and stimulate the growth of a number of bacterial groups, especially Bifidobacterium and Lactobacillus, and eliminate or reduce the number of unfavourable micro-organisms in our organism - adds Prof. Kapelko-Żeberska.

Fatty acids formed in the large intestine affect the metabolism of the entire body, especially the synthesis of cholesterol and triglycerides, and butyric acid plays a key role in preventing the formation of colorectal cancer.

- And, importantly, the fermentation of resistant starch influences the increase in its levels in the large intestine. But it is not only cancer prevention that is important. Food containing resistant starch, compared to that which is rich in fully digested starch, causes glucose to be released slowly after a meal, thus reducing the insulin response. Reducing glucose and insulin levels in the blood is beneficial for diabetics and healthy people alike - emphasises the scientist from the Division of Carbohydrate Technology, adding that reducing the energy value of food, prolonging the feeling of satiety due to the slow release of glucose into the blood and increasing intestinal filling can be used in the nutrition of people who are overweight.

Research on resistant starch has led to the distinction of five fractions. The RS1 fraction is a starch physically inaccessible to digestive enzymes. RS2 starch is a non-gelatinised starch of certain plant species. RS 3 starch is a retrograded starch, which is a substance precipitated from a starch glue or gel in the process of retrogradation. The RS4 fraction is physically or chemically modified starch that is not susceptible to digestive enzymes. Resistant starch type RS5, on the other hand, is starch which resistance to amylolytic enzymes is due to the formation of starch-fat complexes that prevents the enzyme from accessing the starch chain.

- Nowadays, most resistant starch products are obtained by chemical modification, but growing nutritional awareness is causing consumers to be critical of the quality and composition of the products they buy. This, in turn, raises the need to look for alternative solutions using natural raw materials and processes. My project concerns a methodically narrow scope of research. Thermal re-polymerisation is a process that occurs during roasting, the intensity of which depends on the roasting conditions and presumably on the amount and type of starch hydrolysates formed during thermolysis - says Prof. Małgorzata Kapelko-Żeberska, emphasising that hypothetically the addition of a starch hydrolysate to starch during roasting may not only accelerate the processes taking place during roasting, but also intensify them, resulting in resistant starch (RS4) by means of its physical modification with the product of its natural (enzymatic) hydrolysis.

What do the elderly eat?

Dr. Robert Gajda from the Department of Human Nutrition will carry out his project in collaboration with the Wrocław Centre for Social Development. The survey will be conducted in a sample of people aged 65 and over from Wrocław and the Wrocław area - questionnaires will be sent to approx. 500 people, and 100 will be repeated after 4 weeks to validate the survey. The questionnaire, developed by Dr Robert Gajda to identify dietary risk factors, contains 107 questions with responses based on a 7-point Likert scale (answers: definitely no, rather not, don't know, rather yes, definitely yes). The questions relate to dietary risk factors, i.e. changes in body weight, food intake, dietary intake, and physiological, adaptive and social problems hindering nutritional rationality. As part of the statistical analysis, confirmatory factor analysis will be used to identify a senior nutrition risk assessment questionnaire model to determine the number and structure of factors and their interrelationships and interactions, which will be considered when modelling the questionnaire design.

- There is no Polish questionnaire for studying the nutritional risk of seniors living in local communities. Dietitians and doctors often need to rely on a the Canadian-developed questionnaire SCREEN-14 - Seniors in the Community: Risk Evaluation for Eating and Nutrition, which does not take into account the diversity of the local community, and includes, for example, questions about puddings, which are virtually non-existent in traditional Polish cuisine, as well as tofu or beans in sauce, which are also uncommon in the daily nutrition of Polish seniors - says Dr. Robert Gajda, immediately explaining the difference between nutritional risk and the risk of malnutrition: - There is a consensus on the definition of malnutrition, but at the same time most of the screening tools developed so far, despite some of them having nutritional risk in their name, are nevertheless used to assess the risk of malnutrition, especially in a hospital setting, or sometimes in the local community.

The questionnaire, which will be developed by the scientist from the UPWr Department of Human Nutrition, will be a prototype for the first Polish validated and adapted questionnaire to assess the nutritional risk of Polish seniors, and there are plans to use it in a research project submitted in another competition.

- This model will be the first stage. The next ones are not only intended to validate the questionnaire, but first and foremost promote it in the scientific community, which will give us the opportunity to identify and 'map' nutritional risks among the elderly in Poland - explains Dr. Robert Gajda, immediately adding that identification and 'mapping' will also involve analysis of the relationship between nutritional risk and individual, economic and environmental determinants, with malnutrition, being overweight, obesity, morbidity and mortality. These steps will allow scientists to identify the health and social threats posed by the dietary risks of elderly Poles, and subsequently develop a strategy to eliminate the factors responsible for these risks.

– The risk of malnutrition of the elderly is estimated at approx. 18.8%  in hospitals, 18.5% in nursing homes and 5.2% in the local community. Nutritional risk is a rather general term and refers to factors related to nutritional problems that do not necessarily indicate malnutrition, but which if left unaddressed can become a cause of malnutrition, and we know from research that between 61.5% and 70.1% of elderly people have a high level of nutritional risk - says Dr. Robert Gajda, who is the author of the first Polish publication presenting the results of this research on human nutrition - in Poland the risk among the elderly is as high as 77.5%. - But this result is based on a study conducted using the Canadian SCREEN-14 questionnaire. We therefore need a reliable, custom-made tool that takes into account local specifics, in other words what the average Polish senior citizen who cooks for themselves really eats, which is usually traditional home cooking.

A Central Statistical Office report on seniors - from December 2021 - shows that at the end of 2020 there were 9.8 million people aged 60 and over, an increase of 1.0 percent on the previous year. Of the 9.8 million people aged 60 and over, 85.5 percent (8.1 million) were unemployed in 2020, living off a pension or disability benefit. Among the 1.4 million employed elderly citizens, 38.7 percent had the right to a pension. Social benefits in households consisting solely of elderly citizens accounted for 84.7 percent of disposable income. Around 4.3 percent of the elderly lived in extreme poverty last year, which is an increase of 0.6pp compared to 2019. According to a forecast by the Central Statistical Office, the population of people aged 60 and over in Poland is expected to increase to 10.8 million in 2030, and reach 13.7 million in 2050.

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