Sugar & the heart

We are well aware that too much added and free sugar isn’t great for health, impacting mood, energy, the liver, and also the health of your heart.

In fact, research has found that those who consume at least 15% of their daily energy from sugar – found in the apparent sweet stuff, such as cakes, soft drinks and sweets, as well as everyday packaged products, such as jam, bread and flavoured dairy – have an increased risk for heart disease.

The study

In a prospective analysis that included 26,190 people, 2,493 incident cases of coronary events were identified at a 17-year (on average) follow-up.

At the start of the study, none of the participants had diabetes or a history of cardiovascular disease (CVD).

Sucrose intake was obtained from an interview-based diet history method, including 7-day records of prepared meals and cold beverages and a 168-item diet questionnaire that included other foods.

The researchers found the more sucrose in the daily diet, the greater the impact on heart health.

“Among the 5 per cent of participants who got at least 15 per cent of their daily energy intake from sucrose, the risk of myocardial infarction increased by about a third”, said Emily Sonestedt, the study’s nutrition researcher.

This was even after adjustment for other CVD risk factors, including lack of physical exercise; smoking; dietary intake of fat, fruit and veg; and drinking too much booze.

Overconsumption of the sweet stuff and its effects on heart health has been reflected in other research.

The good news is cutting intake can help reduce the risk for the most common type of heart disease, coronary artery disease (CAD).

Too much sweet stuff to handle

Added sugar and heavily refined, ultra-processed foods are very prevalent in our modern diets. As That Sugar Film raises, the major concern is that many of us do not realise we are overeating these foods that are harmful to health.

The pathways toward compromised heart health due to excessive added sugar intake are many and complex. They may include increased levels of oxidative stress and inflammation, increased blood pressure, and compromised liver function.

In the liver, excess added sugar can be stored in the body as fat, whether from glucose or fructose. The liver undertakes the metabolism of the simple sugars and, through separate mechanisms, can convert each to glycogen – the stored form of cellular energy.

But when the excess energy storage tank is full (which is most of the time for most of us), fructose is stored as fat. This becomes a burden on the liver. As it gets fatty, its function is further compromised.

In turn, levels of fatty triglycerides (TGL) rise in the blood. High levels increase the risk for CAD, even independent of other factors for CVD, such as obesity, insulin resistance, low HDL cholesterol, and lifestyle factors such as exercise and alcohol intake.

The effects of high TGL include decreased HDL cholesterol levels, the presence of atherogenic lipoproteins, increased blood viscosity, hyper-coagulability, and endothelial dysfunction. With those factors present, the development of CAD is imminent.

Have yourself a healthy heart!

It is important to note that for most people, consuming triglycerides through fatty foods contributes only a little to blood triglyceride levels. The leading cause of high fasting or postprandial triglyceride levels is fatty liver and a diet high in simple sugars and heavily refined starchy carbohydrates.

With that in mind, here are a few things to consider for heart health include:

• Limiting added and free sugars and heavily refined and processed grains. A little is fine* but we must be aware that added sugars can easily sneak into packaged or ready-made foods commonly thought to be healthy.
• Limiting unhealthy fats, especially heavily processed oils and artificially created trans-fatty acids, served up in fried foods and partially hydrogenated oils.
• Enjoying healthy fats, including sources of omega-3 fatty acids, such as walnuts, flaxseed, chia seed, leafy greens, and oily fish, which may help to lower TGL, and whole food or minimally processed sources of monounsaturated fats, such as nuts, seeds, avocado and extra virgin olive oil.
• Enjoying real, whole foods, especially vegetables. The fibre helps eliminate excess TGL and cholesterol, and the antioxidants can help mitigate cellular damage.
• Getting exercise, good quality sleep and managing stress.

By Angela Johnson (BHSc Nut Med.)

*Aim to limit intake of free and added sugars to 6 teaspoons (25g) per day, as the World Health Organization recommends. This equates to around 5% of total daily energy intake.