What foods and drinks make a difference?

There is plenty of dietary advice out there – and a lot of dietary supplements that supposedly improve your health. But only a very small number of the recommendations have been proven to help in high-quality research. So a lot of them can be ignored.

If you want to change your eating habits, it’s best to follow recommendations that are based on solid scientific evidence. Most experts agree that people shouldn’t eat or drink too much of the following:

• Very sugary foods and drinks
• Highly processed foods such as instant or canned soups, breakfast cereals, potato chips and sugary yogurts
• Foods with a lot of saturated and trans fatty acids in them, like animal fats and fried foods
• Salt
• Alcohol

There are various reasons for these recommendations. One important thing is to keep an eye on your calorie intake. Eating and drinking too many sugary or highly processed products can increase the long-term risk of becoming overweight. Saturated fats and trans fatty acids are more likely than other fats to have a negative effect on cholesterol. Too much salt can make your blood pressure go up.

It is sometimes claimed that drinking moderate amounts of alcohol (in red wine, for example) is good for the heart. But there’s no scientific proof that this is true. On the contrary: Alcohol tends to increase the risk of many heart diseases.

You don't have to avoid anything completely, though. It is difficult to stick to very strict diets, anyway. But there are good reasons to generally avoid unhealthy foods, only eating them occasionally and in moderation – and then really enjoying them.

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Most of the cholesterol in our blood is made in our body. This means that eating habits only have a limited effect on cholesterol levels.

What role do different types of fat play?

A person's total fat intake doesn't have a major impact on their risk of cardiovascular disease. But the type of fat is important. There are three main types:

• Saturated fatty acids tend to increase the level of harmful cholesterol in the blood (LDL cholesterol). They are mainly found in animal fat but are also found in some solid vegetable fats, such as palm oil or coconut oil. Research has shown that people were able to lower their risk of cardiovascular disease by reducing their intake of saturated fatty acids.
• Unsaturated fatty acids have less of an effect on LDL cholesterol. They're mainly found in vegetable oils and fats like olive oil, avocados, nuts and seeds. They're also found in fish.
• Trans fatty acids are an industrial byproduct of the process of solidifying vegetable oil. They can also occur when vegetable oil is heated to a high temperature to be used for deep-frying, for instance. Trans fatty acids resulting from food processing are considered to be particularly harmful.

In Germany and the rest of the EU, industrially produced trans fatty acids are not allowed to make up more than 2% of the total fat content of a food product. As a result, trans fatty acids have almost disappeared from certain products that used to contain large amounts of them – like margarine.

Dairy and meat products from cows, goats and sheep may also contain trans fatty acids. This is because special enzymes in their stomach turn other fatty acids into trans fatty acids. Naturally occurring trans fats have a different chemical structure from industrial trans fats, and appear to have fewer negative health effects. There is no legal upper limit for them in food products.

Experts don't always agree when it comes to different types of fat in foods. For example, there are different views about the importance of the type of food saturated fatty acids come from and their exact chemical structure. One of the reasons for this is that it's difficult for researchers to produce reliable findings when it comes to diet.

Which food products are high in saturated fatty acids and what are the alternatives?

The following table lists examples of food products that are high in saturated fatty acids – and healthier alternatives. If you're thinking of making changes to your diet, it's important they're ones you can stick to. Research findings show that it takes at least two years for the health benefits to kick in.

The following tips can further help you to cut down on saturated fatty acids:

• Check the fat content of dairy products: the less fat overall, the less saturated fatty acids.
• Cut off any visible fat on meats.
• When choosing fats and oils, it can help to know that saturated fats (like butter, palm oil and coconut oil) are solid at room temperature and unsaturated fats (like olive oil or rapeseed oil) are liquid at room temperature.

In figures: What are the benefits of a diet with less saturated fat?

Several studies have looked into how reducing saturated fatty acids in your diet affects the risk of cardiovascular disease. Each study compared two groups: One group was given support to replace saturated fatty acids in their diet with unsaturated fatty acids, while the comparison group was not.

The idea was that reducing the intake of saturated fatty acids would reduce the risk of cardiovascular disease. After two or more years, cardiovascular disease had developed in

• 85 out of 1,000 people who hadn't changed their diet, and
• 70 out of 1,000 people who had changed their diet.

But there was no effect on life expectancy.

The studies left some questions unanswered: For example, only women took part in the largest study. Men have a higher risk of cardiovascular disease, though, so they may benefit more from a change in diet. What's more, the participants in the studies were only followed for a few years and most of them were over 50 years old. So it's not clear what effect an earlier, long-term change in diet would have. It's also not possible to draw any conclusions about the effectiveness of changing your diet compared to (or in addition to) taking medication to reduce cholesterol levels.

Why are people often advised to follow a "Mediterranean diet"?

The term "Mediterranean diet" describes a diet rich in vegetables, fruits, legumes, nuts, olive oil, whole grain products, fish and poultry. It meets many of the recommendations for a nutritionally balanced diet.

Research has shown that eating this type of diet helps reduce risk factors for cardiovascular disease. One major study also found that the risk of vascular disease (affecting the blood vessels) decreased over a five-year period.

Why does exercise help?

The vast majority of experts recommend regular exercise to strengthen your heart and blood vessels. As well as having a positive impact on your cholesterol levels, exercise and sports can keep your blood vessels fit and make them more elastic. This can reduce blood pressure, too. Exercise can also

• help you to lose weight,
• strengthen your muscles and bones, and
• improve your general fitness and wellbeing.

How much exercise is recommended?

The World Health Organization (WHO) recommends that adults should do

• at least 150 to 300 minutes of moderate-intensity endurance exercise per week, or
• 75 to 150 minutes of high-intensity endurance exercise per week, or
• a combination of the two.

The WHO also recommends that adults should

• do muscle-strengthening activities (like weight training) on two days per week, and
• include a lot of physical activity in their day-to-day activities and spend less time sitting.

Endurance exercise includes things like Nordic walking, hiking, jogging, cycling and swimming. If you haven't done much in the past, it's best to increase your level of physical activity gradually. You can ask your doctor which types of sports would be good for you, whether there are any reasons not to take up certain sports, and how best to get started.

According to the WHO, any endurance exercise that lasts at least 10 minutes has a positive effect. It doesn't matter if you exercise for 30 minutes in one go or incorporate three 10-minute activities into your day.

Many people find it easier to stay motivated if they

• do physical activities with their family or friends,
• start off slowly and then gradually do more,
• keep a record of their activities on a smartphone app or fitness tracker.

The important thing is to find something you enjoy doing and that fits in with your day-to-day schedule.

What role does body weight play?

Being obese (very overweight) increases the risk of cardiovascular disease. People are considered to be obese if they have a BMI of over 30. Generally speaking, the higher the BMI, the higher the risk of illness.

People with a BMI above 30 are advised to lose 5 to 10% of their weight. They can only do this by changing their diet over the long term. Exercise can help but it’s not enough on its own. Various programs can help you lose weight.

Why is it helpful to give up smoking?

Smoking can increase the amount of LDL cholesterol (“bad” cholesterol) in the blood. But it damages the blood vessels in other ways too: It can cause small areas of inflammation on their inner walls, increasing the risk of deposits and blood clots in those areas. Smoking also causes the coronary arteries (the vessels that supply the heart) to become narrower.

Research shows that smoking significantly increases the risk of cardiovascular disease and that the risk is higher the more a person smokes. If they manage to give up, that can also help to prevent cancer and lung disease and increase their overall life expectancy.

Most smokers do manage to stop if they’re motivated enough but it often takes a few attempts. The right preparation, support and special products to help reduce withdrawal effects (like nicotine replacement therapy) can help here.

Do certain dietary supplements reduce cholesterol?

A wide variety of products are claimed to reduce cholesterol and be good for your cardiovascular health. Many of these products are sold as highly concentrated dietary supplements in the form of capsules. But no supplements have been proven to prevent medical problems such as heart attacks or strokes.

Examples of supplements that have not been proven to help here include:

• Artichoke extract
• Fish oil
• Garlic
• Guggul
• Policosanol (a sugar cane extract)
• Products containing soluble fiber such as psyllium husk
• Green tea extract (catechin extract)

Experts even recommend avoiding certain supplements. For instance, good-quality, large-scale studies carried out in recent years have repeatedly shown that fish oil capsules containing omega-3 fatty acids increase the risk of an irregular heartbeat (atrial fibrillation). Omega-3 fatty acids are also found in food – for example, in linseed oil and rapeseed oil, linseed and walnuts.

Generally speaking, even if a supplement does improve a person’s cholesterol levels, that doesn’t mean that it will also decrease their risk of developing medical problems such as a heart attack. Cholesterol levels alone cannot prove that a treatment is effective.

Sources

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• Curfman G. Omega-3 Fatty Acids and Atrial Fibrillation. JAMA 2021; 325(11): 1063. [PubMed: 33724309]
• De Souza RJ, Mente A, Maroleanu A et al. Intake of saturated and trans unsaturated fatty acids and risk of all cause mortality, cardiovascular disease, and type 2 diabetes: systematic review and meta-analysis of observational studies. BMJ 2015; 351: h3978. [PMC free article: PMC4532752] [PubMed: 26268692]
• Hall KD, Ayuketah A, Brychta R et al. Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake. Cell Metab 2019; 30(1): 67-77.e63. [PMC free article: PMC7946062] [PubMed: 31105044]
• Hooper L, Martin N, Jimoh OF et al. Reduction in saturated fat intake for cardiovascular disease. Cochrane Database Syst Rev 2020; (8): CD011737. [PMC free article: PMC8092457] [PubMed: 32827219]
• Hooper L, Summerbell CD, Thompson R et al. Reduced or modified dietary fat for preventing cardiovascular disease. Cochrane Database Syst Rev 2012; (5): CD002137. [PMC free article: PMC6486029] [PubMed: 22592684]
• Laranjo L, Ding D, Heleno B et al. Do smartphone applications and activity trackers increase physical activity in adults? Systematic review, meta-analysis and metaregression. Br J Sports Med 2021; 55(8): 422-432. [PubMed: 33355160]
• Rees K, Takeda A, Martin N et al. Mediterranean-style diet for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev 2019; (3): CD009825. [PMC free article: PMC6414510] [PubMed: 30864165]
• Schwingshackl L, Zähringer J, Beyerbach J et al. A Scoping Review of Current Guidelines on Dietary Fat and Fat Quality. Ann Nutr Metab 2021 [Epub ahead of print]: 1-18. [PubMed: 33789278]
• Wood G, Taylor E, Ng V et al. Determining the effect size of aerobic exercise training on the standard lipid profile in sedentary adults with three or more metabolic syndrome factors: a systematic review and meta-analysis of randomised controlled trials. Br J Sports Med 2021.
• World Health Organization (WHO). Guideline: Sugars Intake for Adults and Children. Geneva: WHO; 2015.
• World Health Organization (WHO). WHO guidelines on physical activity and sedentary behaviour. Geneva: WHO; 2020.

• IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

  Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. informedhealth.org can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

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