Popular low-carb diets can lead to 'dangerous' rise in cholesterol, study finds

Low-carb diets have become increasingly popular, touted for their ability to keep blood sugar levels and weight down and slash the risk of diabetes. But new research suggests the trendy diet could send cholesterol levels sky-rocketing for some, increasing the risk of heart disease, heart attack and stroke. Around half of UK adults are estimated to have high cholesterol, the deadly fatty plaque that builds-up in the arteries and kills around one in five every year. Low-carb diets are typically made up of 75 per cent fat, 20 per cent protein, and 10 per cent carbs, like potatoes and bread.The eating plan has previously been credited with raising levels of so-called good cholesterol, which helps clear fatty deposits from the arteries. However, new findings suggest that the diet could increase 'bad' LDL cholesterol in high risk individuals due to the high fat foods it entails. Presenting the research, study lead author Alexa Barad said while some may see benefits with a low-carb diet, this doesn't apply to everyone. 'Diet advice can sometimes be presented as one-size fits all,' she said. 'While some people find a low-carb diet raises their cholesterol, others see no effect.' The keto diet is a high-fat, low-carb plan designed to force the body to burn fat for fuel instead of glucose The team, from Stanford University School of Medicine, wanted to see if a person's genes could help identify those who could benefit from eating fewer carbohydrates, and those who may experience a potentially deadly rise in cholesterol. The study analysed data from a trial involving more than 600 adults who followed either a healthy low-carb diet or a healthy low fat-diet for one year.First, the authors identified no clear advantage for either diet when it came to weight loss.But the current researchers wanted to take this one step further, focusing on 431 participants for whom genetic data was available. They examined participants' individual genetic makeup, saturated fat consumption, and changes in 'bad' cholesterol over a six-month period. Among participants eating a low-carb diet, those who were genetically predisposed to higher levels of bad cholesterol were more likely to experience a potentially dangerous increase, the scientists found.This was said to be because those following the diet often replace carbohydrate-heavy food for those that are high in fat, such as red meat and cheese. High cholesterol causes fatty deposits to build up in the arteries, which can narrow the blood vessel and lead to a heart attack Participants with the highest genetic risk experienced the largest increases in bad cholesterol when they consumed more saturated fat.The team hope that their method will one day help doctors and nutritionists identify people who are more likely to experience harmful cholesterol changes with certain diets. Saturated fats are found in many foods, but most of them come from animal sources including meat and diary products. Palm oil is also a saturated fat. Unsaturated fats, meanwhile, are mostly found in plants and fish. In the UK, current guidelines recommend that saturated fat should make up no more than around 10 per cent of a person's daily calorie intake.For men, this means no more than 30g of saturated fat a day, while women are advised to limit their daily intake to no more than 20g. NHS guidance recommends cutting down on saturated fat and replacing it with unsaturated fats including omega-3 fats where possible, to minimise the risk of heart disease. For those following a low-carbohydrate, this means choosing foods like nuts, seeds, and olive oil over butter, fatty cuts of meat and processed meats, which are high in saturated fat. Around 200,000 people a year suffer a heart attack or stroke in the UK, making cardiovascular disease the UK's biggest killer.An estimated eight million people are living with cardiovascular disease – a group of conditions affecting the heart and blood vessels that can increase the risk of heart attack and stroke.Around 100,000 Britons suffer a stroke each year and the condition – which occurs when blood stops flowing to part of the brain – is one of the nation's leading causes of death, claiming around 34,000 lives annually.