In a recent podcast with Dr. Robert Lustig, a leading expert in endocrinology, an intriguing light is shed on the complex relationship between genetics, environmental factors, and our diet. Dr. Lustig emphasizes a crucial insight: while our genetic code has remained virtually unchanged over the past 30 years, our environment, especially our diet, has undergone a dramatic transformation. These changes have profound implications for our health and well-being.
The immutable nature of human genetics
Human genetics is remarkably stable and evolves only gradually over many generations. Within the relatively short span of three decades, no significant genetic shifts have been observed within the human population. This observation is crucial, as it demonstrates that the recent increase in obesity and other metabolic diseases cannot be directly attributed to changes in our genes.
The dynamic changes in our environment
Over the past decades, however, we have seen significant changes in two key aspects of our environment: our diet and our lifestyle.
Diet: There has been a noticeable shift in our eating habits. We are increasingly consuming processed foods that are high in refined sugars, particularly fructose, and unhealthy fats. At the same time, there is a decrease in the consumption of fresh, unprocessed foods that contain essential nutrients like fiber, vitamins, and minerals.
Lifestyle: In addition to these dietary changes, we have also witnessed a shift in our lifestyle, with a decrease in physical activity and an increase in sedentary behaviours.
The health consequences
These changes in diet and lifestyle have led to an alarming increase in metabolic diseases. We are witnessing a rise in the incidence of obesity, Type 2 diabetes, heart diseases, and certain forms of cancer. A particularly worrying development is the increase in insulin resistance, largely caused by the heightened intake of sugar, especially in the form of fructose. This insulin resistance plays a key role in the development of various metabolic disorders.
Fructose vs. glucose metabolism
Different metabolism: Unlike glucose, which is utilised by nearly all cells in the body, fructose is primarily metabolised in the liver. This unique metabolism of fructose has significant health implications.
Processing in the liver: When fructose reaches the liver, it triggers a series of biochemical reactions. Unlike glucose, which is regulated by insulin and used for energy, fructose is directly converted into fat.
Health issues related to fructose consumption
Obesity: Fructose contributes to weight gain by increasing fat production in the liver. This fat can be stored in the liver and other parts of the body, leading to obesity.
Type 2 diabetes: Due to the way fructose is metabolised, it contributes to insulin resistance, a key factor in the development of type 2 diabetes. Insulin resistance means that the body becomes less sensitive to insulin, leading to higher blood sugar levels.
Liver fat accumulation (non-alcoholic steatohepatitis, NASH): The increased fat production in the liver due to fructose consumption can lead to liver fat accumulation, a condition where excessive fat accumulates in liver cells.
High blood pressure (Hypertension): Fructose can increase blood pressure through various mechanisms, including raising urate levels in the blood, which can lead to narrowing of the blood vessels.
Heart diseases: The combination of obesity, insulin resistance, liver fat accumulation, and hypertension increases the risk of cardiovascular diseases.
Mechanisms of fructose and insulin resistance
Fat production and VLDL: Fructose stimulates the liver to produce triglycerides, a type of fat that is transported in the blood as VLDL (Very Low-Density Lipoprotein). High levels of VLDL are a risk factor for heart diseases.
Insulin signalling: Due to the way fructose is metabolised, it can disrupt normal insulin signalling, leading to insulin resistance. This means that the cells become less sensitive to the effects of insulin, which is essential for regulating blood sugar levels.
Fructose consumption, especially in the form of added sugars in processed foods and sweetened beverages, contributes to a range of health problems. The unique metabolism of fructose in the liver and the resulting effects on fat production.
Integration of fructose in foods:
The food industry has increasingly integrated fructose, mostly in the form of high-fructose corn syrup (HFCS), into a wide range of products. This is not limited to obvious choices like soft drinks and sweets, but also extends to less obvious items such as bread, sauces, and breakfast cereals.
Marketing tactics: Through aggressive marketing campaigns, targeting both adults and children, the consumption of sugary products has been significantly promoted. Many of these products are advertised as ‘essential’ or ‘healthy,’ despite their high sugar content.
Economic considerations: The relatively low cost of HFCS compared to other sweeteners makes it an attractive option for manufacturers to use in their products.
Government policy and regulation:
Subsidies and agricultural policy: In certain countries, like the United States, government policy has supported the production of corn and HFCS through subsidies, making these ingredients cheaper and more attractive for food manufacturers.
Nutritional guidelines: There is criticism of how government guidelines have addressed the role of sugar in diets. Dr. Lustig argues that these guidelines do not sufficiently emphasise the risks associated with excessive sugar consumption.
Labeling and regulation: There is criticism of the lack of strict regulations around the labelling of sugary products, often resulting in incomplete knowledge amongst consumers about the amount of sugar they are consuming.
Health consequences
Increase in metabolic disorders: The increased consumption of fructose is linked to a rise in metabolic disorders, including obesity, type 2 diabetes, and liver diseases.
Addiction and overconsumption: Dr. Lustig points out that fructose, especially in the form of HFCS, can have addictive properties. This leads to overconsumption and contributes to the development of health problems.
Simplification of food labels and sugar regulation
Complexity of food labels: In many countries, including the United States and member states of the European Union, there are regulations for food labelling. However, these rules can often be complex or even misleading, making it difficult for consumers to accurately determine the amount of added sugars in products.
In the United States: The Food and Drug Administration (FDA) has established guidelines for food labeling, including the listing of added sugars. More information about these guidelines can be found on the FDA website regarding changes to the Nutrition Facts Label.
In the European Union: There is also EU legislation for food labelling. Although this legislation currently does not specifically require the listing of added sugars, more information about the current labelling standards can be found on the EU website about food labelling.
Various names for sugar: Sugar can appear under different names, such as glucose syrup, fructose, sucrose, and maltose. This makes it challenging for consumers to identify the actual sugar content in food products.
Policy proposals for improved labelling:
More transparent labelling: Proposals are in circulation to simplify and make labelling more transparent, especially regarding the listing of added sugars.
Educational campaigns: Governments and health organisations are encouraged to conduct awareness campaigns to inform the public about sugar consumption and healthy eating.
Tax on sugary drinks: In some countries and cities, taxes on sugary drinks have been implemented to reduce their consumption. An example of this is the sugar tax in the United Kingdom, which you can read more about on the UK government’s website about the Soft Drinks Industry Levy.
These policy issues and proposals play a crucial role in the fight against the negative health effects of excessive sugar consumption. Through improved labelling and increased awareness, consumers can make better-informed choices about their food consumption.