Health Impacts of Sustainable Ingredient Selection in the Food and Drink Industry - ALTERNATIVE PROTEIN STUDY
Condition: Healthy
Study type: Interventional

Summary: 
      Summary

      This research will examine the nutritional effects of supplementing diets with alternative
      plant sources of protein with potential to be grown in Scotland. In particular, we will
      assess the potential of these plant protein sources to complement diets in which the
      predominant source of protein is meat. These protein sources will include plants from the
      Fabaceae, Cannabaceae and Polygonaceae families, which could be used as the basis for the
      development of new foods. The research will assess if these plant proteins can deliver a
      comparable alternative to meat based diets.

      It is anticipated that the results could encourage increased consumption of plant products
      which would be favorable for consumers shifting away from animal-derived proteins for health
      and/or environmental reasons.

      Hypothesis: Consumption of protein rich plants could be a sustainable and healthy choice for
      partial replacement in predominantly meat based diets.

      Objective: The objective of this acute study is to assess satiety, postprandial effects,
      metabolite bioavailability and metabolism of single alternative proteins from a shortlist
      including buckwheat, fava beans, lupin, pea, and hemp in comparison with red meat.

      Study protocol

      Aims: To assess the impact of a pea, fava bean, lupin, hemp, buckwheat in comparison with
      meat in healthy people on:

        -  Biomarkers of satiety as measured by gut-related hormones and subjective appetite using
           visual analogue scales, specifically to be collected during the meal over a three hour
           period, every 30 minutes. The energy intake measured for each volunteer after an ad
           libitum lunch (five hours after test meal).

        -  Biomarkers of CVD risk including total cholesterol, low density lipoproteins (LDL), high
           density lipoproteins (HDL), triglycerides and non-esterified fatty acids (NEFA).

        -  Assessment of peripheral glycaemic control, fasting glucose, area under the curve
           combined with insulin data.

        -  Plasma and urine markers of important phytochemical and protein metabolites will be
           quantitatively analysed to determine the systemic availability, in vivo concentrations
           and excretion times.

        -  Volunteer views towards diets rich in plant proteins will be assessed.
    

Detailed description: 
      Background

      Recent scientific evidence suggests that diets largely based on plant foods, such as
      well-balanced vegetarian diets, have potential to improve health, in contrast with
      predominantly meat-based diets. However, many consumers may not wish to exclude meat from the
      diet, despite current advice to reduce, in particular, processed meat. One way to achieve
      this is to increase consumption of plant-based protein components in the diet.

      Making a comparison of the nutritional content of high protein plants (i.e. those with > 20 g
      protein/100 g dry weight), several candidate sources were identified. In particular, these
      belong to the Fabaceae family and include pulses (green peas, fava beans, lupin seeds) and
      certain common bean species. Species from plant families other than the Fabaceae generally
      have less protein. An exception is hemp seed (Cannabaceae family), which can have a protein
      content around 40g protein /100g dry weight, is a source of fibre, and has favourable fatty
      acid and amino acid profiles. Other families of interest include the Amaranthaceae species
      (Quinoa), Polygonaceae (Buckwheat) and the Poaceae (Wheat, Barley and Oats). Protein content
      of these pseudocereal and cereal crops ranges from 12-20 g protein /100 g dry weight.
      Although lower in protein content compared with the Fabaceae species, they are generally rich
      in fibre and consequently will impart additional benefits to a high-protein plant based diet.

      According to the Scottish Health Survey (2009), nearly two-thirds of men (66.3%) and
      approximately half of women (58.4%) were overweight. Obesity is a major risk factor for
      metabolic syndrome, which is linked to conditions such as type II diabetes mellitus (T2DM).
      Having impaired glucose tolerance doubles the chance of morbidity and mortality from
      cardiovascular disease (CVD). CVD is the leading cause of death and accounts for nearly 30%
      of deaths worldwide each year. Clinical studies have shown that regular consumption of pulses
      can reduce blood levels of total cholesterol and low density lipoprotein (LDL).

      The recent meta-analysis of randomized controlled trials provides the strongest evidence to
      date that non-soya legume consumption lowers serum total and LDL cholesterol and therefore,
      may lower the risk of CVD. Eating pulses regularly may also lower CVD risk via favorable
      effects on blood pressure, blood glucose and insulin levels and by satisfying hunger and
      helping manage body weight. Higher legume intakes were associated with lower body mass index
      (BMI), blood pressure, serum total cholesterol (TC) and a lower incidence of T2DM, compared
      with lower legume intakes. In addition to achieving energy balance and improving the overall
      diet, the World Health Organization (WHO) recommends that people increase consumption of
      legumes (pulses), as well as vegetables, wholegrain and nuts to prevent obesity. There does
      not seem to be differential effects of pea-protein as compared to other meat and dairy
      proteins when fed at similar amounts as a pre-load.

      Technically a nut, hempseed typically contains over 30% oil and about 25% protein, with
      considerable amounts of dietary fibre, vitamins and minerals. The two main proteins in
      hempseed are edestin and albumin (high-quality storage proteins are easily digested and
      contain nutritionally significant amounts of all essential amino acids); hempseed has
      exceptionally high levels of the amino acid arginine. Hempseed is an excellent source of
      nutrition and has been used to treat various disorders for thousands of years in traditional
      medicine. Animal studies and only few humans study (on hemp seeds oil) agree as well that
      hempseed has health promoting properties; supported by results from nutritional analyses of
      the seed, oil and seed meal. Being a rich source of polyunsaturated fatty acids and proteins
      which contain all of the essential amino acids in nutritionally sufficient amounts as
      detailed by the FAO/WHO (Food and Agriculture Organization of the United Nations/World Health
      Organization) suggested requirements for infants or children. Hemp proteins have a Protein
      Digestibility Corrected Amino Acid Score (PDCAAS) equal to or greater than certain grains,
      other nuts, and some pulses. Hempseed, in addition to its nutritional value, has demonstrated
      positive health benefits, including the lowering of cholesterol and high blood pressure.

      Buckwheat has attracted increasing attention from food scientists for its potential
      beneficial effects in chronic diseases. In the early 1970's the nutritional properties of
      buckwheat were first demonstrated. The cholesterol lowering effects of buckwheat protein
      extracts in rats with cholesterol-enriched diets has been reported.

      There has been much research conducted on the functionalities and properties of buckwheat
      proteins and other phytochemicals in buckwheat seeds. Among them, the most promising are the
      flavones, flavonoids, phytosterols, fagopyrins, and the thiamin-binding proteins. Buckwheat
      proteins have unique amino acid compositions Experiments, both in animal models and with
      human studies revealed that buckwheat flour can improve T2DM, obesity, hypertension,
      hypercholesterolemia and constipation.

      For the social science element of the project, the proposed study will employ qualitative
      research methods which emphasise the importance of 'lay' knowledge and the subjective
      experience of research participants. Within the field of nutrition research, qualitative
      methods and techniques still remain comparatively rare. This is partly because of the
      privileged status of quantitative research, but also because of the length of time and amount
      of effort that goes into each qualitative study and the small pool of qualified researchers
      in this field .As qualitative research efforts require that researchers seek to understand
      people and the social and cultural contexts in which they live from the participants' points
      of view, this type of knowledge has much to contribute to our understanding of why people eat
      what they do. For the purposes of this study, qualitative methods will enhance our
      understanding of the acceptability, to consumers in Scotland, of foods based on sustainable,
      plant-based protein. It will also tell us much about any barrier that exist to the uptake of
      such foods, from a consumer perspective.

      Planned work for the study

      From a health perspective it is essential to establish the bioavailability and metabolism of
      plant proteins and other dietary constituents in humans. Certain metabolites are absorbed
      early in the gastrointestinal tract, whereas others are transported to the colon where they
      are extensively metabolized by the gut microbiota. In this acute study, we will characterise
      the bioactive metabolites present in the urine and plasma samples obtained. This will inform
      on their availability to the systemic circulation, as well as their excretion profiles. We
      will employ targeted quantitative analysis using both LC-MS and GC-MS which will provide the
      identity of metabolites and their in vivo concentrations. We will focus on metabolites that
      are considered to impact on human health. The principal metabolites analysed will be those
      produced by the phenylpropanoid pathway and products of protein and carbohydrate metabolism.
      These will include derivatives and metabolites of the simple phenols, benzoic acids, phenolic
      acids, phenylacetic acids, phenypropionic acids, phenylpyruvic acids, phenyllactic acids,
      mandellic acids, phenolic dimers, acetophenones, benzaldehydes, cinnamaldehydes, benzyl
      alcohols, cinnamyl alcohols, indoles, isoflavones, coumarins, chalcones, flavanones,
      flavones, flavonols, anthocyanidins. We have also shown that many of these compounds are
      bioactive and exhibit anti-oxidant and anti-inflammatory activity at in vivo concentrations.
      These studies will provide important information on bioavailability and metabolism, but will
      also allow us to correlate the indices with biomarkers of health. In this study we will also
      examine the effect of different protein sources on post-prandial effects, endocrine responses
      (e.g. PYY (peptide YY) levels) and hunger ratings. The energy intake for each volunteer will
      be measured after lunch (ad libitum) on the intervention day. Volunteer views and
      acceptability towards diets rich in plant protein will be assessed. Some components in pulses
      may contribute to weight control by inhibiting intestinal absorption of carbohydrates and
      other energy yielding nutrients such as protein. Correlating the metabolic profiles with
      biomarkers of health will provide information that will be fed back into agricultural
      practice to optimise crop breeding strategies for benefits on human health.

      With regard to the social science component of the project, in-depth semi-structured
      interviews will be used. The term 'semi-structured' reflects the intrinsic flexibility of
      qualitative interview approaches, which often use an aide-memoire or interview guide rather
      than a formal schedule. In addition, the form and content of the research questions is likely
      to vary, in response to each particular interview context. This type of built-in design can
      strengthen qualitative research because of its attentiveness to context.

      All interviews will be digitally recorded and fully transcribed. The qualitative analytical
      techniques applied will look for and examine the themes and patterns of meaning within the
      kinds of data generated by this research mode. The interviews and conversations that take
      place as part of qualitative inquiry will generate responses, perceptions, opinions and so on
      from research participants. These can be understood as constituting a 'discourse' (or set of
      ideas) derived from the focus of the inquiry that lends itself particularly well to thematic
      analysis. Themes are derived by the process known as 'coding' (or labelling) specific chunks
      of text according to the ideas which they seem to represent. This interpretative work
      involves the creation of analytical themes by the researcher and is particularly useful in
      bringing together the 'insider' or 'emic' perspective derived from the research participant's
      knowledge and experience, with the 'outsider' or 'etic' perspective of the researcher and the
      relevant literature. Patterns in the data are thus identified through the intellectual work
      of bringing together components or fragments of ideas, perceptions or experiences which might
      be meaningless when considered in isolation. The researcher engaged in thematic analysis
      seeks to understand how different ideas or components fit together in a meaningful way, in
      order to produce a coherent analytical account.

      The analysis will be validated by referring back to the relevant literature, which may
      support (or counter) inferences drawn by the researcher. The interweaving of research
      findings with extant research literature will help strengthen the interpretive account
      provided by the researcher. Research participants will also be engaged in this process in
      that their feedback on emerging patterns will be sought. This process of member checking will
      be conducted during the course of each interview. Through an analytical framework that
      focuses on discourse and acknowledges the importance of participants' own perspectives and
      experiences, analysis will present a contextualised exploration of the ways in which
      consumers perceive plant-based proteins as alternatives or supplements to meat.
    

Intervention name(s): Fava bean, Lupin, Beef meat, Green pea, Hemp, Buckwheat
Intervention type(s): Other
Intervention description(s): The intervention visit involves a test meal to be consumed by subjects attending the Human Nutrition Unit in the morning, following an overnight fast. The meal will be consumed within 15 minutes and blood (69 mL) and urine samples will be collected during 24 hours.
The test meals are designed to contain the same amount of proteins. Alternative protein meals: a number of bread buns for each meal containing individual alternative protein flours (green pea, lupin, hemp, buckwheat, fava beans). These will deliver 30 g of protein, the remainder being provided by white flour. The control (meat) meal: a lean beef steak containing 30 g of protein and a bun containing the same amount of white flour as used for the alternative protein bread buns.
The semi structured interview guide: will take place within the Human Nutrition Unit during one of the scheduled visits, once initial screening has taken place and participants have been selected. All interviews will be digitally recorded.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Alternative sources of plant proteins; High protein diets; Satiety; Postprandial effects; Bioactive phytochemicals; Phytochemicals bioactivity and metabolism; Macronutrients metabolism; Health effects of plant proteins vs. meat proteins; Partial meat proteins replacement with plant proteins; Satiety of meals rich in plant proteins; Postprandial effects of meals rich in plant proteins; Plant phytochemicals and macronutrients bioavailability and metabolism