Ist rotes Fleisch gut oder schlecht für Dich? Eine objektive Betrachtung

October 25, 2023

Is red meat good or bad for you? An objective view

Red meat is the meat of mammals that is normally red when raw. It is one of the most controversial foods in the history of nutrition. Even though humans have eaten it throughout evolution, many believe it is harmful.

Below is a review of the scientific views on the effects of red meat on health. This article focuses only on the scientific facts and leaves out ethical or environmental considerations.

Today's meat is not what it used to be

Humans have eaten red meat for much of human evolution and our digestive systems are well designed to digest this type of food.

Traditional populations such as the Masai ate much more red meat than the average Westerner and still enjoyed excellent health (1).

However, the meat consumed today is different from the meat that people used to eat. Back then, animals roamed freely and ate grass, insects or other foods that were part of their natural diet.

Imagine a wild cow in a field 10,000 years ago, free to roam and eat grass and other edible plants. The meat of these animals is different from the meat of a cow that has been raised in a factory farm, fed a grain-based diet and given growth-promoting hormones and antibiotics on top of that.

Today, some meat products are heavily processed after the animals have been slaughtered. They are smoked, cured and treated with nitrates, preservatives and various chemicals.

For these reasons, it is important to distinguish between different types of meat:

Processed meat: These products usually come from conventionally raised cows and go through different processing steps. Examples include sausage and bacon.
Conventional red meat: Conventional red meat is largely unprocessed, but usually also comes from industrially bred animals. Meat that is red in color when raw is defined as red meat. This includes lamb, beef, pork and others.
White meat: Meat that is white in color when cooked is defined as white meat. This includes meat from poultry such as chicken and turkey.
Organic meat from grass-fed animals: This meat comes from animals that have been naturally fed and raised without drugs or hormones. The feed of these animals is also free from added chemicals.

When considering the effects of meat on health, it is important to realize that not all meats are created equal.

Many studies conducted on red meat - especially those conducted in the U.S. - primarily looked at meat from factory-farmed animals raised on grain-based diets.

Summary: It is important to distinguish between different types of meat. Organic meat from grass-fed animals is nutritionally different from meat from animals raised on grain-based feed.

Red meat is very nutritious

Red meat is one of the most nutritious foods you can eat. It is packed with vitamins, minerals, antioxidants and numerous other nutrients that have positive effects on your health.

100 grams of raw ground beef with 10% fat contains (2):

Vitamin B3 (niacin): 25% of the daily requirement
Vitamin B12 (cobalamin): 37% of the daily requirement (this vitamin is not found in plant-based foods)
Vitamin B6 (pyridoxine): 18% of the daily requirement
Iron: 12% of the daily requirement (this is high-quality heme iron, which can be absorbed by the body much better than plant-based iron)
Zinc: 32% of the daily requirement
Selenium: 24% of the daily requirement
Plenty of other vitamins and minerals in smaller amounts

In addition, 100 grams of beef provides 176 kcal, 20 grams of high-quality animal protein and 10 grams of fat.

Red meat is also rich in important nutrients such as creatine and carnosine. Vegetarians are often deficient in these nutrients, which can potentially impair muscle and brain function (3, 4).

Meat from grass-fed cattle is even more nutritious than meat from grain-fed animals, as it contains plenty of heart-healthy omega-3 fatty acids, the fatty acid CLA and higher amounts of vitamins A and E, among other things (5, 6).

Summary: Red meat is highly nutritious, especially when it comes from naturally fed and raised animals. It is an excellent source of protein, iron, vitamin B12, zinc, creatine and numerous other nutrients.

Heart disease, diabetes and death

The effects of red meat on health have been well studied. However, most of these studies are so-called observational studies, which are designed to detect associations but cannot prove causality.

Several observational studies have shown that red meat may be associated with a higher risk of cardiovascular disease, cancer and death (7).

However, not all types of red meat have the same effects on health. A massive review of 20 studies with a total of 1,218,380 participants found that processed meat was associated with an increased risk of heart disease and diabetes. However, this link could not be established for unprocessed red meat (8).

In the EPIC study - a very large observational study with 448,568 participants - processed meat increased the risk of death, while no such effect was observed for unprocessed red meat (9).

When it comes to increasing the risk of heart disease, diabetes and death, it is crucial to distinguish between processed and unprocessed meat, as these two types of meat can have very different effects.

The observational studies seem to agree that processed meat (and not unprocessed red meat) is associated with an increased risk of early death and many diseases.

However, it is important to keep in mind that these studies have their limitations. It is impossible to draw strong conclusions from observational studies. The only way to determine cause and effect is to conduct randomized controlled trials.

Summary: Several observational studies have shown a link between meat consumption and an increased risk of diabetes, heart disease and death. Other studies suggest that this only applies to processed meat, but not to unprocessed red meat.

Does red meat increase your risk of cancer?

Many observational studies have shown that red meat consumption is associated with an increased risk of cancer (10).

The main type of cancer believed to be caused by red meat is colorectal cancer - the fourth most commonly diagnosed form of cancer in the Western world. A recurring problem with these studies is that they lump processed and unprocessed red meat together.

Meta-analyses, which scientists use to analyze data from different studies, show that the increased risk of colorectal cancer is very low. One meta-analysis found a weak association in men, but no association in women (11).

Other studies suggest that it is not the meat itself, but harmful compounds produced when meat is cooked that contribute to the increased risk (12). Thus, the method of preparation may be an important determining factor when it comes to the ultimate health effects of meat.

Summary: Several observational studies show that people who eat red meat have a higher risk of cancer, but larger reviews that look at the big picture show that this effect is weak and inconsistent.

Correlation does not equal causation

If you take a closer look, virtually all of the studies that purport to prove that red meat is harmful are observational studies.

These types of studies can only show correlation, which means that two variables are related. They can tell us that people who eat a lot of red meat are more likely to get sick, but they can't prove that red meat is the cause.

One of the main problems with such studies is that they are all plagued by different confounding factors. For example, people who eat red meat are often less health conscious and are more likely to smoke, drink, consume more sugar, exercise less, and so on.

People who are health conscious behave differently from people who are not and it is impossible to remove all these factors from the study results.

Another problem with observational studies is that they are usually based on surveys about the consumption of different foods and subjects are expected to remember what they have eaten in the past.

It is always a bad idea to make health decisions based on observational studies alone. There are many cases in history where randomized controlled trials ended up showing exactly the opposite effect.

The so-called Nurses Health Study once showed that estrogen replacement therapy helped reduce heart disease in women. Later, randomized controlled trials discovered that estrogen actually increased the risk (13).

Summary: Observational studies cannot be used to determine cause and effect. There are many confounding factors in such studies and higher quality studies sometimes end up showing the exact opposite.

A look at some randomized controlled trials

Randomized controlled trials are the gold standard of science. In these studies, subjects are randomly assigned to groups. For example, one group is given diet A and another group is given diet B. Scientists then observe the subjects to find out which diet is more likely to lead to a particular result.

Several randomized controlled trials have been conducted to directly examine the effects of red meat on health. A few studies also examined the effects of red meat on risk factors for heart disease.

One review of controlled trials concluded that eating half a portion of red meat per day did not affect risk factors for heart disease such as blood lipid levels and blood pressure (14).

Another review showed that lean, unprocessed beef does not increase blood lipid levels compared to poultry and fish (15).

As a rich source of protein, red meat can also support muscle growth in people who do weight training.

A study conducted on women showed that eating 160 grams of red meat six days a week increased muscle growth as a result of strength training compared to pasta and rice (16). Red meat also reduced levels of the inflammatory marker IL-6.

It should be kept in mind that all of these studies looked at lean red meat. To date, there are no studies that have investigated the effects of fatty red meat on health.

However, there are numerous studies that have compared high-fat and low-fat diets.

These studies have the primary goal of reducing saturated fat, which means that the subjects in these studies eat less red and processed meat, which is rich in saturated fat.

The Women's Health Initiative is a study that involved 46,000 women. One group was instructed to eat a low-fat diet, while the other group continued to eat the typical Western diet.

After a period of 7.5 years, there was hardly any difference in weight (0.4 kg) between the groups. There was also no difference in the rate of heart disease and cancer (17)

A randomized controlled trial compared the Atkins diet (which is rich in red meat) with the Ornish diet (a low-fat, vegetarian diet without red meat). This study is also known as the A to Z weight loss study (18).

After one year, the Atkins group had lost more weight and showed greater improvements in some of the major risk factors for disease.

Many other studies compared low-carbohydrate diets (which were high in red meat) with low-fat diets (which were low in red meat). In these studies, low-carbohydrate diets resulted in much better outcomes (19, 20).

Taken together, these studies suggest that unprocessed red meat does not negatively affect health and may even have health benefits.

However, further studies are needed to investigate whether it affects so-called "hard endpoints" such as heart disease or cancer. The role of cooking and processing techniques also needs further investigation.

Summary: Several randomized controlled trials suggest that eating unprocessed red meat has no negative effects on health. It may even have benefits.

The basics of optimizing red meat consumption

When meat is cooked at high temperatures, harmful compounds can form. These include heterocyclic amines, polycyclic aromatic hydrocarbons and end products of advanced glycation.

These compounds can cause cancer in animals. If meat does indeed increase the risk of cancer - which has yet to be proven - then this could be the reason (21).

However, this does not only apply to meat. Other foods can also form harmful compounds when heated to high temperatures.

Here are some tips that can help ensure your meat doesn't form these harmful compounds:

Use gentler methods of heating such as braising and stewing instead of grilling and frying. 2. Minimize cooking at high temperatures and never expose meat to open flames.
Do not eat charred or burnt meat. If your meat is burnt, cut off the affected pieces.
Marinating your meat with garlic, red wine, lemon juice or olive oil can significantly reduce the amount of heterocyclic amines.
If you have to cook meat at high temperatures, turn it regularly to prevent it from burning.

Many people like the taste of roasted and grilled meat. However, if you want to enjoy meat without the potential negative consequences, you should choose gentler methods of preparation and avoid burnt meat.

Summary: To avoid the formation of harmful substances, you should choose gentler methods of heating and avoid burnt meat.

Conclusion

If you look behind the scare tactics and sensationalist headlines, you will realize that there is no strong evidence linking red meat to human disease.

There are only observational studies, which often do not distinguish between red meat and processed meat.

Furthermore, these rely on surveys of dietary habits and simply cannot adequately account for complicated confounding factors such as the health consciousness of the subjects.

Observational studies can provide clues and are important for generating theories, but they cannot test those theories.

As long as you use unprocessed and preferably grass-fed meat, make sure to prepare it gently and avoid burnt parts, there is probably nothing to worry about.

In fact, properly prepared red meat is probably very healthy.

It's highly nutritious and packed with healthy proteins, healthy fats, vitamins and minerals, and numerous other nutrients that are known to positively impact body and brain function.

References:

Source: https://www.healthline.com/nutrition/is-red-meat-bad-for-you-or-good

By Kris Gunnars, BSc

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