Why is food so important to our health?
The influence of our diet and the foods we eat on our health is a vast subject, and with new discoveries been made all the time, we are yet to have the full picture.
Nonetheless, the extensive impact that foods can have on our health and general well-being is well documented, and creating long term healthy eating habits can have numerous health benefits.
Food habits and behaviours are complex and influenced by many components; including socioeconomic factors such as income, education, and ethnicity; lifestyle factors including knowledge and attitude; and physiological factors such as appetite.
Poor diet quality is a primary risk factor for non-communicable diseases; responsible for 63% (36 million) of global deaths in 2008.
In developed countries people consume unprecedented quantities and varieties of foods, shifting away from local or seasonally produced foods. Yet we are faced with extreme malnutrition; from obesity to hunger and nutrient deficiencies.
The global obesity and diabetes epidemics indicate we are unhealthier than ever before.
Excessive consumption leading to childhood obesity is currently at the forefront of western public health agendas, due to excess weight affecting over 25% of school children in some European countries and America.
As a result, ‘The Childhood Obesity Plan’ was launched in the UK in 2016, which outlines several aims including the reduction of the sugar content of popular brands by 20% by 2020. A high prevalence of unhealthy habits is also observed in university students, though they are often overlooked in public health campaigns.
The Obesogenic environment
The obesogenic environment is a term used to describe the environmental factors that make becoming overweight much more likely in western societies.
Access to increasingly cheaper, larger, tastier and more calorific foods, has cultivated and shaped the obesogenic environment. Both marketing and the media have a large part to play in creating this environment.
For example; several marketing mechanisms influence the amount of food consumed; the short and long-term price of foods, adverts and promotions, the quality and quantity of products, and the eating environment.
The food industry’s tactics and techniques are comparable to those previously employed by the tobacco industry, due to the emphasis on consumer responsibility, their lobbying power and pre-emptive self-regulation. The food industry spends a huge amount of money on advertising, with numerous studies concluding unhealthy food adverts are associated with childhood obesity.
The media is undeniably a valuable tool to influence food habits, however it currently seems to be having an overwhelmingly negative effect. In many developed countries, people are constantly exposed to both manipulative advertising designed to increase consumption, as well as unrealistic, enhanced images of the ‘ideal’ body type.
Othorexia nervosa is an eating disorder characterised by an unhealthy obsession with eating healthily, which typically leads to an extremely restricted diet that can have severe health consequences, and often prevents the individual engaging in social activities.
Two hot topics in food and health
Sugar and artificial sweeteners – an ongoing debate
It’s well documented that excessive sugar consumption is linked to obesity, tooth decay and overall poor health and well-being, though other factors including exercise, saturated fat and portion size are also important.
It is difficult to address all the complex variables simultaneously, however evidence shows obesity is largely preventable and reducing energy intake is an important factor. Reducing sugar consumption has therefore become a key public health message, resulting in many companies offering sugar free options as an alternative.
How healthy is calorie free?
Though products containing non-nutritive (calorie free) sweeteners are advertised as healthier or diet versions, observational evidence suggests non-nutritive sweetener consumption is associated with adverse effects including weight gain, central obesity, cardiovascular disease, and metabolic syndrome.
A similarly increased risk of type 2 diabetes and non-alcoholic fatty liver disease is associated with the consumption of both regular and diet soft drinks, though the association with diet beverages is no longer significant after body weight is taken into account.
Paradoxically, randomised control trials, the gold standard of research, have shown neutral or positive effects associated with the use of non-nutritive sweeteners for weight management, creating a confused picture.
Sweeteners vs Sugar
Long-term studies are lacking, but do conclude that non-nutritive sweeteners have a positive effect on energy intake, body weight, liver fat, and glycaemia when compared to sugar. The important thing to note here is that the control is sugar, and therefore is not neutral.
The role of the food industry & sweeteners
Adding to the inconsistencies, sweet solutions containing non-nutritive sweeteners, particularly aspartame, have been observed to increase motivation to eat. Aspartame is 200 times sweeter than sucrose and therefore only very small amounts are required to sweeten foods. While industry-funded studies conclude aspartame is safe and palatable, 92% of independently-funded studies suggest adverse health effects.
The food industry promotes non-nutritive sweeteners as metabolically inert, however one study proposed that in fact they bind to gut sweet taste receptors and stimulate insulin secretion by the pancreatic B-cells. Though this is not yet a widely accepted theory, it is supported by a small clinical trial documenting increased insulin levels in humans following non-nutritive sweetener consumption.
What does this all mean?
Gut sugar sensing mechanisms are only partially understood, but overall the evidence questions the use and promotion of non-nutritive sweeteners, so regular and prolonged consumption may not be beneficial for your health.
Gut health and microbiota
An area of research showing incredibly interesting results is the field of gut microbes, with some scientists now referring to the gut as our ‘second brain’ due to its extensive effects on the body through hormone secretion and signalling. The link between our gut microbiota and disease is being repeatedly shown, and is not limited to only diseases affecting the gut.
The composition of our gut bacteria is shown to be shaped both in the womb and in infancy, for example children who are breastfed have a noticeably different profile to those who are not.
Good and bad bacteria
The type of bacteria that colonise our intestine in infancy can affect the efficacy of the gut barrier, and potentially predispose an individual to the development of inflammatory diseases later in life (study can be found here).
The gut microbiota is susceptible to change as a result of external influences, including diet, and an imbalance in gut bacteria is linked to several diseases and mental health conditions (study can be found here).
Fermented foods are an increasing health trend which is unlikely to slow down in 2018, with examples including kefir and kimchi. These foods contain large amounts of probiotics, and during fermentation the bacteria produce compounds called biologically active peptides, which are well known for health benefits, such as reduced blood pressure (more information on the benefits of fermented foods can be found here).
Gut health and fibre
Closely linked to gut health is the intake of dietary fibre. Fibre is often overlooked in discussion surrounding diet and health, and underrated in terms of the health benefits it can yield. Just an extra intake of 7g of fibre per day is associated with a significant reduction in bowel diseases, such as diverticular disease.
The current recommended intake in the UK is 30g/day however survey data suggests average intake falls well short of this, therefore increased awareness is undoubtedly needed.
Dietary fibre is also fermented by gut bacteria to produce short-chain fatty acids, which are associated with significant beneficial effects on cell turnover, metabolism and eating behaviour.
The other beneficial effects of fibre include reduced blood pressure, reduced risk of cardiovascular disease, reduced transport time of food in the gut, increased stool frequency and weight, increased satiation (feeling of fullness), reduced c-reactive protein and reduced glucose absorption rate. In particular, fibre is an important consideration for those following a low carb or paleo diet, in which intake is often particularly low.
How to maintain a balanced diet
With so much conflicting information in the media, trying to follow a balanced diet can be a challenge.
Often restrictive diets are promoted as being the fix for becoming healthier, though these tend to be unsustainable and unrealistic. The use of phrases such as ‘clean eating’, ‘cheat meals’, and ‘guilt-free’ encourage a negative relationship with food, something that should be enjoyed.
Indulging in a treat every now and again should not be something to feel guilty about, and in fact most people will reduce the amount they eat the following day after an indulgent meal without even realising. This is part of the body’s way of maintaining a constant weight despite daily intake fluctuations.
Though we often see single foods, such as turmeric for its anti-inflammatory properties, promoted as the answer to a healthy diet, overall diet quality is becoming the focus of research. It is much more advisable to look at your diet as a whole and assessing whether you are getting all the nutrients and vitamins required, rather than putting too much attention on a single food or food group.
This article has only touched upon a few areas in an incredibly complex and large topic, but hopefully highlights the significant impact that diet has and can have on our health, both in the more obvious ways such as obesity, as well as through less well-defined mechanisms.
Significant shifts towards following national dietary guidelines, and eating primarily unprocessed foods are needed and will help to form the basis of healthy diets, upon which foods shown to have specific health benefits can be added.