VOL: 97, ISSUE: 44, PAGE NO: 50
Shupikai Rinomhota, MSc, RGN, RMN, PGCE, RNutr, is nursing lecturer, University of Leeds
Hazel Rollins, MSc, RGN, RM, is nutrition specialist nurse, Luton and Dunstable Hospital NHS TrustThe type of food and amount of energy consumed affect both health and general well-being. However, even though individuals may be aware that their diet is unhealthy, they may not make appropriate changes. As well as affecting mood and general well-being, food intake is also affected by the individual's mental state and social environment.
The type of food and amount of energy consumed affect both health and general well-being. However, even though individuals may be aware that their diet is unhealthy, they may not make appropriate changes. As well as affecting mood and general well-being, food intake is also affected by the individual's mental state and social environment.
During examination periods, students show both physical and emotional components of anxiety that can lead to compensatory 'comfort eating' (Fieldhouse, 1985). This results in altered patterns of eating - large meals become unappealing and are replaced by less healthy items such as sweet, high-calorie chocolate bars and soft drinks.
Most parents would testify that, from time to time, children will shun healthy family meals in preference for unhealthy sweet, high-fat snack-type foods. In children who do not normally exhibit such behaviour this usually occurs when they are going through high anxiety-provoking experiences.
There is also enough anecdotal evidence to support Fieldhouse's view that many adults use food to help them manage anxiety, boredom, disappointment, frustration, irritability, loneliness, tension and unhappiness.
Physical activity versus dietary behaviour
One significant factor affecting energy intake is the relationship between physical activity and dietary behaviour. Gillmann et al (2001) examined the relationship between physical activity and dietary quality and found that sedentary individuals consumed less healthy foods and nutrients such as fruits, vegetables, antioxidants vitamins and non-starch polysaccharides (fibre) than more active individuals.
The sedentary individuals' diets tended to be high in cholesterol, saturated fats and trans-fatty acids (found in milk, butter and other dairy products, margarine, meat, meat products, fish, eggs and cereal-based foods), all of which may be detrimental to health in high quantities.
Trans-fatty acids provide about 6% of the dietary fat intake in the UK diet (Eastwood, 1997). Work by Gillmann et al (2001) supported an earlier study by Rolland-Cachera and Bellisle (1986) which concluded that the socially accepted level of daily energy intake influences the development of overweight and obesity by challenging individuals' adaptive capacity. Failure to adapt to excess energy intake by undertaking exercise or acting to reduce intake results in obesity.
Many obese people are found in groups where there is generally a large daily intake of energy and where overweight is relatively well accepted.
Hence, it can be argued that failure of such individuals' regulatory process is environmentally facilitated and that body weight regulatory mechanisms will have been challenged beyond their adaptive threshold. This may be the elusive point. Do our bodies respond to food intake as a challenge and either adapt to it or fail to adapt to it?
While the focus has been on the role of macronutrients, it is important to mention that both minerals and vitamins influence mood and behaviour. Many vitamins and minerals have a role in what is known as intermediary metabolism, where they allow metabolic processes to occur smoothly. The B complex vitamins, which include thiamine, riboflavin, niacin, panthothenic acid, pyridoxine, lipoic acid and biotin, all have a role in intermediary metabolism (Linder, 1991). Even a short-term deficiency of thiamine (B1) leads to general fatigue, weakness and emotional fatigue (Lishman, 1998) while pyridoxine (B6) deficiency is characterised by fatigue, nervousness, irritability, depression and insomnia (Westermarck and Antila, 1994).
In healthy adults, folic acid deficiency leads to insomnia, irritability, fatigue, forgetfulness and, most commonly, depressive symptoms (Alpert and Fava, 1997). Reynolds (1967) found that folic acid supplementation in folate-deficient people with epilepsy resulted in increased drive and initiative and elevation of mood. Carney et al (1990) argued that folic acid deficiency is most strongly associated with endogenous depression (depression from within), rather than with neurotic depression. Unfortunately, despite the well-publicised role of folic acid during pregnancy in the prevention of neural tube defects such as spina bifida the intake of folic acid in the general population has not improved significantly, due to unhealthy life-styles and eating habits. The role played by selenium, zinc and copper in immune function and by iron in general well-being should not be underestimated.
Thiamine (B1) and lipoic acid in intermediary metabolism
Lipoic acid, a cofactor (vitamin-like substance) that is synthesised in the body (Brody, 1999), is found in all tissues, although the amount synthesised is not known (Linder, 1991). Whitney et al (1998) described lipoic acid, together with inositol and choline, as 'vitamin impositors', since they are not generally essential but are needed by the body under certain circumstances. Yeast and liver are good sources of lipoic acid, which contains sulphur (Linder, 1991; Reed, 1980).
Thiamine (B1) and lipoic acid play an important role in intermediary energy metabolism by linking processes where no oxygen is used (anaerobic reactions such as glycolysis) with those where oxygen is used (aerobic reactions) such as citric acid cycle. Thiamine is converted to thiamine pyrophosphate (TPP), while lipoic acid is attached to the amino acid lysine to form lipoamide. This then forms acetyllipoamide, which transfers an acetyl group to co-enzyme A. In other words, TPP and lipoamide act as cofactors and, through a series of reactions, enable the transfer of an acetyl group to co-enzyme A, resulting in the formation of acetyl CoA. It is this acetyl CoA that allows the carbohydrates we eat to enter the citric acid cycle for oxidisation under aerobic conditions (Stryer, 1996; Zubay, 1998).
The consumption of alcohol interferes with the effective use of essential nutrients, while its calorific value increases energy intake. Alcohol also affects mood state (Rinomhota and Marshall, 2000). Due to their higher body fat mass, women metabolise alcohol differently to men, and after a defined dose of alcohol they achieve a higher blood alcohol concentration than men (Suter et al, 1997). In an earlier study of free-living individuals, Suter et al (1995) found a significant relationship between drinking frequency and body weight gain. Alcohol has a relatively high energy content at 7.1kcal/g, and this leads to weight gain if intake is significant. Some of the reasons ascribed to alcohol consumption include induction of relaxation, increased sociability and reduction of anxiety, with the overall effect being alteration in mood (Simpson, 1992).
Traditional eating practices affect the consumption of carbohydrates, proteins and fats and may be influenced by a facilitatory environment. There is still a need to clarify unequivocally the effect of individual nutrients on mood and behaviour. However, both mood and anxiety affect food intake through the use of comfort-eating as a mechanism for coping with stress. Any measures adopted to tackle weight gain and obesity should take a holistic perspective. In particular we need to acknowledge the special relationship that individuals have with food.