Nicolette Gibson Hall

Dietary protein quality and malnutrition in Africa

The WHO (2007) Technical Report on protein and amino acid requirements in human nutrition states that the best estimate for a population average requirement is 105 mg nitrogen/kg body weight per day, or 0·66 g protein/kg body weight per day. In many developing countries protein intake falls significantly short of these values. Apart from protein quantity, protein quality including bioavailability and digestibility, from different food sources, are currently on the global agenda. The 1st International Symposium on Dietary Protein for Human Health held in Auckland, in March 2011, and the consecutive Food and Agricultural Organization of the United Nations (FAO) Expert Consultation on Dietary Protein Quality, both highlighted the importance of assessing the quality of protein from different food sources through determination of amino acid content. Throughout the developed world, animal products and cereals are the two most important sources of protein; in developing countries this order is reversed. In low income countries only 3 % of total dietary energy, as an indicator of diet composition, is derived from meat and offal, 11 % from roots and tubers and 6 % from pulses, nuts and oilseeds. The remainder of the dietary energy is mainly derived from cereal-based staple food. Although the production of livestock has increased in developing countries, the consumption of protein in these countries with people consuming the most limited amounts of protein are continually decreasing. Undernutrition, including insufficient consumption of protein, remains a persistent problem in the developing world, and although many diets within these developing countries are deficient in the quantity of protein compared to recommendations, the quality of the protein also strongly comes into focus.

Total nitrogen vs. amino-acid profile as indicator of protein content of beef

In most cited food composition studies and tables, the proximate system measures protein as total nitrogen (N) (determined by Kjeldahl or Dumas method) multiplied by a specific factor. A factor of 6.25 is used for determining total protein from total N (Jones, Munsey, & Walker, 1942). Although more expensive, it is considered more accurate to base protein content of foods on amino acid data (Greenfield & Southgate, 2003). A study on the nutrient composition of beef analysed the full amino-acid profile of fifteen retail cuts from three age groups and six fat codes, as well as determined total nitrogen content to determine proximate protein composition. For all cuts, the correlation coefficient of total amino acids to protein (N×6.25) was 0.635. This indicates a poor correlation for predicting actual protein content (as determined by total amino acid count), based on the nitrogen factor of 6.25. On average, the sum of amino acids per cut amounted to 91% of total determined protein (N×6.25) for the same cut.

Capacity building in food composition for Africa

Capacity building in food and nutrition involves more than formal training and individual development. Such a process is long term and continues, requiring lasting mentorship, coaching and leadership development, including individual commitment to continued self-development. It expands to include the development of knowledge and skills of an individual within his/her organizational or institutional arrangements, and requires buy-in and support from his/her institution or organization, as well as other funding bodies involved in agriculture and health. It needs to be supported by government and be part of the regional and international agenda for agriculture and health. Under the auspices of International Network of Food Data Systems (INFOODS), an African Network of Food Data Systems (AFROFOODS) was established in September 1994, and a number of training courses, educational and scientific publications, posters, presentations and visits were hosted, organized and delivered with the aim to build enthusiasm, long term commitment and capacity in food composition within the AFROFOODS region. Formal training and human resource development were the major focus to take food composition forward in Africa. Significant progress was made in food composition activities, but constraints including lack of organizational and institutional commitment and financial support are straining the pace of progress.

Effect of animal age and trimming practices on the physical composition of Bonsmara beef

Increased economic incentive for producing young and leaner carcasses, as well as demand for lean meat from progressively health conscious consumers, are considered drivers for change in carcass composition over time. Furthermore, many retailers trim visible fat from meat to various degrees and consumers increasingly remove visible fat from meat prior to, or after, cooking. The objective of this study was to determine the composition of South African Bonsmara beef from four age groups from different production systems, as well as to extrapolate the effect of fat trimming on physical composition. Fat content of marketable beef has decreased notably since the 1930s, and beef from the South African Bonsmara breed contains less than 10g lipid per 100g after trimming of subcutaneous fat, irrespective of age. Removal of all visible fat reduces the lipid content to less than 5g per 100g, comparing favourably with other lean animal products.

Total and haem iron content lean meat cuts and the contribution to the diet.

This study provides data on the total and haem iron contents in raw lean beef, chicken, lamb and pork meat samples. Total iron, expressed as mg/100g edible portion on fresh weight basis in raw lean beef (A-age), lamb, pork and chicken average 1.58, 1.64, 0.81 and 0.78, respectively. The haem iron content in beef (A-age), lamb, pork and chicken are 77%, 81%, 88% and 74% respectively of total iron. This has important dietary implications in calculating haem iron fractions of meat as this is higher than the common value used in the Monsen equation.

The role of traditional foods in food-based dietary guidelines - a South African case study on maas (cultured milk)

With the revision of the South African food-based dietary guidelines (FBDGs) a new guideline specifically recommending the daily consumption of dairy products including maas (cultured milk) was introduced. This paper aims to evaluate the relevance of including maas as a traditional food product in the FBDGs. It was found that maas is a culturally relevant and traditional food product in South Africa. The nutrient profile of maas has changed notably over time since the first nutrient analysis was performed in 1995. The health benefits of maas, together with its popularity and its cultural relevance as part of the South African diet, make maas a suitable traditional food product to be included in the South African FBDGs.

The nutrient content of selected South African lamb and mutton organ meats (offal)

The Research Technology Fund of the National Research Foundation and Red Meat Research and Development of South Africa.

Bioavailability of Nutrients

Bioavailability aims to describe the effect of metabolic events on nutrient utilization. The supply of nutrients to the human body depends not only on the amount of a nutrient in food but also on its bioavailability. The bioavailability of nutrients is highly variable and can be influenced by numerous factors. Different nutrients (including protein, iron, and vitamin A), and the forms in which they exist in the ingested medium, will react in different ways to inhibitors and enhancers as well as the hosts nutritional status, all of which contribute to nutrient bioavailability.

The important role of food composition in policies and programmes for better public health: A South African case study

Most governments have committed to the set of Sustainable Development Goals established by the United Nations (UN) to be achieved by 2030. Subsequently the governments have drafted, or are in process of drafting, policies and programmes which aim to answer to these global requests. South Africa provides a unique case study: despite economic growth, undernutrition has not improved when compared to other industrialised nations, while at the same time, diet-related non-communicable diseases and obesity have exponentially increased. Access to healthy food is a constitutional right of all South Africans, and towards increasing food security and improving population health, various policies, programmes and regulations have been developed and implemented by the government to rectify the situation. The paper presents an overview of food composition within these public health policies, programmes and regulations and unpacks the important role of accurate food composition data.

Fatty acids in beef from grain- and grass-fed cattle: the unique South African scenario

Abstract Objective: Different fatty acids elicit different responses in the human body once ingested. Although red meat is often considered to be a source of fatty acids which has a negative impact on human health, many studies have reflected variability in the quantity and quality of fatty acids found in red meat produced on different production systems in different countries. This study evaluated the fatty acid profile of beef, produced by the grass- and grain-fed production systems practised in South Africa. Design: Data are reported as a percentage of lipid per 100 g total fat to enable a comparison with international findings. Furthermore, the findings are translated into edible meat portions, taking fat trimming (often associated with red meat intake) into consideration in order to determine the contribution which the different products can make to the human diet. Subjects and setting: Three cuts of beef from cattle from four production groups were sampled and the fatty acid composition analysed for the meat and fat fractions. Results: Notable differences were found in the quantity and quality of different fatty acids in beef from the different production systems. When untrimmed, no statistically significant difference was found in the total fat between beef produced on the different production systems. Differences became more significant as trimming was performed. When trimmed of all visible fat, beef from young cattle fed according to a grain-based feeding system contained less total fat (6.96 g), and less saturated fat (2.16 g) per 100 g, than beef produced from their grass-fed counterparts (9.77 g and 3.30 g, respectively). There was a more favourable omega-6 to omega-3 fatty acid ratio, i.e. 2.0–2.5:1.0 for grass-fed cattle, compared to 8–30:1 for grain-fed cattle, irrespective of the degree of trimming. The beef from the grass-fed cattle also contained a higher quantity of conjugated linoleic acid. Conclusion: A unique classification system for red meat has been implemented in South Africa and dictates the characteristics of the fresh meat that is available to consumers. The results of this study consequently indicate distinctive differences between the fatty acid profile of local red meat and that of beef produce from other countries; often used as a reference for dietary guidance.