Cardiovascular disease (CVD) is the primary cause of death worldwide, and in England, CVD is the second most common cause of death. This month marks National Heart Month, an opportunity to raise awareness of the impact diet can have on heart health.
Factors like age, gender, ethnicity, and family history can increase your risk of CVD, and unfortunately, you cannot change these. For example, if you’re South Asian, African, or African Caribbean in the UK, your risk of developing some heart and circulatory diseases can be higher than white Europeans.
However, there are many more modifiable factors that you can control to reduce your overall risks, such as monitoring blood fat levels, blood pressure, blood sugar levels, smoking, activity levels and your fat to muscle ratio.
Excluding exercise and smoking, all the above can be modified by dietary changes - great news! We know that improving your diet can help modify many inflammatory processes which can lead to heart disease (G.F. Watts et al., 1992).
Importance of Dietary Patterns
Over the past decade, recommended dietary guidelines surrounding heart health have undergone a shift from single nutrient-based approaches to dietary pattern-based approaches. One example of this is following the Mediterranean diet. Although it differs throughout places and cultures, in general, it includes high amounts of fruit, vegetables, legumes, and wholegrains; a moderate amount of unsaturated fats such as olive oil, avocado, nuts and seeds, dairy products, fish, and poultry, and low intakes of red meat and wine, saturated fats, and simple sugars. This dietary pattern has seen a reduction of major CVD events by 30% and a decrease in type 2 diabetes incidence (Carlos S., et al., 2018, Becerra-Tomás N., et al., 2020).
The Portfolio diet is another good example of an evidence-based dietary pattern shown to reduce CVD risk factors (Chiavaroli L., et al., 2018). More specifically, this works on lowering cholesterol, by including more soy protein, plant sterols, nuts, and soluble fibre in the diet. Emphasis should be placed on making dietary changes rather than worrying about which individual saturated fatty acids are more harmful to your heart and whether we should eat 5, 8 or 10 portions of fruit and veg per day.
Mechanisms of Action
The dietary patterns above are predominantly plant-based, and this is thought to play a large part in their effect on heart health. Fruit and vegetables contain fibre and polyphenols which influence the production of beneficial bacteria: short-chain fatty acids (SCFA). SCFA can exert positive influences on the gut microbiome and its functions, which may have protective properties. The relative risk for heart disease is reduced by 8% for every 200g of fruit and veg consumed each day. Following the 5-a-day guidelines could have a positive impact on your risk of heart disease.
According to the Global Burden of Disease study, more than half of diet-related deaths are related to diets high in sodium and low in fruit, vegetables, nuts, seeds, and wholegrains. Whilst the evidence isn’t conclusive right now, evidence from observational studies indicates that diets rich in whole grains could be protective against coronary heart disease (CHD), and in contrast diets that are low in wholegrains may increase the risk of obesity and cardiometabolic diseases.
Sodium is an essential nutrient in the body, which the body cannot produce itself. Everyone needs to consume sodium regularly, however, a very delicate balance is required - the amount of sodium you eat, or drink has important implications for your health.
The terms sodium and salt are used interchangeably. Salt is made up of sodium and chloride, and the salt purchased from supermarkets to flavour foods usually contains sodium. Evidence shows a clear dose-response effect of reducing salt intake on lowering blood pressure, a heart disease risk factor (Wang, Y.J., et al., 2020). This means that the more that salt intake is reduced, the more that blood pressure decreases. Adults should eat no more than 6g of salt a day (2.4g sodium) – that's around 1 teaspoon. To help keep your intake under control, limit the foods below, common to be high in sodium. In the kitchen, use herbs, garlic, and onions to boost flavour without salt.
Cured meats (e.g., cold cuts like ham, turkey chicken, pork pies and bacon)
Fast and restaurant food
Frozen dinners & other packaged foods
Condiments and sauces
How important is dietary fat?
Although controversial at times amongst health professionals, the current understanding from evidence suggests there needs to be a focus on foods and dietary patterns, rather than the single fat nutrient alone. Cohort studies have shown associations between diet and CHD risk and that reducing fat intake alone isn’t enough – the food that replaces the fat is important too. For example, replacing 5% of saturated fat energy intake with polyunsaturated fatty acids (PUFAs), monounsaturated fatty acids (MUFAs) or wholegrain carbohydrates is associated with a reduced risk of CHD incidence (Y Li., et al., 2015).
The most recent published PREDIMED trial investigated the effects of a Mediterranean diet with added nuts, versus a Mediterranean diet with added olive oil, versus a low-fat control diet. Results showed a 30% reduction in CVD incidence over 5.5. years in both Mediterranean diet groups. Strong evidence that a moderate fat diet rich in unsaturated fats is more cardioprotective than a low-fat diet. Try to focus on unsaturated fats found in almonds, avocados, and good quality vegetable oils like extra virgin olive oil, as well as omega-3 fatty acids from fatty fish. Dietary guidelines are to consume at least 2 portions of fish a week (1 of which should be oily).
Higher total nut consumption is associated with a lower risk of CVD incidence and nut intake has been shown to beneficially modify CVD risk factors such as weight, blood lipids, and inflammation (G. Liu et al., 2019). Of all the food groups, nuts were shown to have the strongest LDL-cholesterol lowering effects in a network meta-analysis of randomised control trials (Schwingshackl L et al., 2018). Just 28g of almonds contains 13 g of unsaturated fat, only 1 gram of saturated fat and absolutely no cholesterol.
A greater intake of fruit and vegetables, wholegrains, nuts, unsaturated fat, and lower consumption of saturated fat and salt, is supported by evidence for the prevention of CVD.
Combining the above suggestions together with maintenance of a healthy weight (moderating energy intake and adequate physical activity) could have a significant impact on lowering your risk of CVD. The health impact of only changing one dietary factor over short periods is likely to be small!
Written by Abigail Attenborough (ANutr)