• So far there have been various theories about the origin of noise.
• Researchers observed the process in the magnetic resonance tomograph.
• There is no indication of whether the cracking is bad or good for the joints.

The cracking noise when pulling apart of fingers formed according to a study by the formation of a cavity in the joint.

Finger in the magnetic resonance tomograph

In the investigation, Greg Kawchuk’s team from the University of Alberta in Edmonton, Canada, took a closer look at a man’s metacarpophalangeal joints in an MRI scanner. The scientists present their results in the journal “PLOS ONE” .

Is there a threat to health?

Some people can crack their joints when they pull their fingers apart. There is currently no evidence as to whether this phenomenon is bad or good for the joints. “So far, no one has ever been able to prove that this  cracking is harmful to health in the long term,” says Professor Jörg van Schoonhoven from the Clinic for Hand Surgery at the Rhön Clinic in Bad Neustadt an der Saale.

Different theories

For a long time there have been various theories about where the popping sound when clicking your fingers comes from. Some scientists suspected that the crackling sound was caused by a bursting bubble in the joint space.

Other researchers hypothesized that the sound is caused by the flapping of ligaments.

Another explanation for the origin of the cracking is what is known as tribonucleation: a mechanism in which the movement of surfaces creates gas bubbles in a liquid.

Study author as guinea pig

To date, there has not been any direct experimental evidence that solidly supports any of the theories. Kawchuk’s researchers wanted to change that. 

For their study, the scientists needed someone who had the ability to crack their metatarsophalangeal joints on request. These joints connect the bones of the metacarpus to the base members of the fingers. The choice fell on Jerome Fryer, one of the study authors.

Pull until it cracks

In the experiment, the researchers examined each finger of the test subject in isolation in a special magnetic resonance tomograph, with which movement sequences can be recorded.

The finger was attached to a kind of tube that was connected to a cable at the other end. Then the cord was pulled until Fryer’s fingers cracked. The entire process in the joint was recorded with an MRI scanner.

Is a cavity the cause?

Shortly before the cracking could be heard, the researchers were able to observe the formation of a cavity in the images.

The scientists therefore assume that tribonucleation has taken place in the joint: “It is a bit as if a vacuum is being formed,” explains Kawchuk in a communication on the study. “If the joint surfaces suddenly separate, there is no longer any liquid left to fill the increasing joint volume. This creates a cavity.” The noise is generated by this event. 

“It is interesting to know what acoustic phenomenon is behind the cracking of the fingers,” said the hand surgeon van Schoonhoven. However, by including only one person in their study, Kawchuk’s researchers would be able to explain the phenomenon only for that person. “The experimental setup does not allow any generalized statements,” said van Schoonhoven.

According to popular belief, those who eat vegetables, fruit and whole grain products every day have a particularly healthy diet – and thus possibly make a dangerous mistake, get fat and sick. The American cardiologist and nutritionist Steven R. Gundry is convinced of this, as he explains in his bestseller “The Plant Paradox”, which has also been available as a German version since this year (Steven R. Gundry: “Bad vegetables. How healthy Food makes us sick ”, Beltz).

Vegetable plants use lectins for defense

Lectins are said to be responsible for the harmful effects of supposedly healthy foods. These are certain proteins that plants have developed for defense so that they are spared from fungi, bacteria and parasites. In fact, lectins act similarly to antibiotics and can be toxic, especially when raw.

The substances can harm people

Lectins make green potatoes and raw beans inedible . The best-known lectin is gluten, avoided by many because it can lead to bowel inflammation and celiac disease . Gluten, known as adhesive protein, illustrates the negative properties of lectins particularly impressively: These proteins are extremely easy to bond, stick to cells and tissues, preferably in the intestine. The mucous membrane cells change, the intestinal wall becomes permeable for pollutants, which in turn can make the entire organism sick.

Sick from lectins – from Alzheimer’s to rheumatism

But not only celiac disease is caused by the harmful effects of lectins. The proteins bind to red blood cells, thicken the blood and thus promote arteriosclerosis and cardiovascular diseases. Steven Gundry also explains many other diseases of civilization with the negative effects of lectins.

Because they can actually dock on all tissues, such as the pancreas, joints, bronchi, nerves, brain, and the immune system attacks them there as intruders, autoimmune diseases would develop: diabetes , arthritis and rheumatism, asthma , Parkinson’s and Alzheimer’s .

These foods are high in lectins

The doctor therefore promotes a diet that is as free from lectins as possible (LFE, lectin-free diet). The negative list of foods rich in lectin includes the following products:

• loaf
• Potatoes and potato products
• rice
• pasta
• Beans and legumes
• soy
• tomatoes
• Cucumbers
• pumpkin
• Grain
• Vegetable oils
• sugar

Steven Gundry also largely avoids fish and meat, or at least restricts consumption – because breeding animals are mainly fed with corn and soy. Both types of food naturally contain lectins. If they are genetically modified, however, they provide even more of it to protect the plants from pests even better. With the feed they get into the animal and thus into the meat that is put on the plate.

How to eat a lectin-free diet

The negative list is long, but there are also a number of foods that contain little or no lectins. The positive list of desirable foods suggests, among other things:

• Coconut oil
• Coconut milk
• Hazelnuts
• Walnuts
• Sweet chestnuts
• Olives
• Tigernut flour, chestnut flour
• Dark chocolate
• cream cheese
• Goat cheese
• butter
• cream
• Crustaceans, fish (rare)
• certain types of fruit in small quantities (apples, pears, blueberries, raspberries, kiwi, plums, peaches, citrus fruits)
• Cabbage vegetables of all kinds
• artichokes
• garlic
• Onions
• Meat (no more than 125 gr per day)
• Eggs
• Sweeteners such as erythritol, stevia, xylitol
• 1 glass of red wine per day

Of course, all products should come from organic cultivation or rearing if possible, i.e. have the best organic quality.

Lectin-free diet – new fad diet or serious prevention and therapy?

At first glance, the impression arises: after fructose, gluten and carbohydrates, lectins are now supposed to be the bad nutrients that lead to obesity and make you sick. But the impression is deceptive. Steven Gundry’s observations should probably be taken seriously. There is some evidence for his theses:

• It has long been known that lectins are unfavorable and are therefore even referred to as ” anti-nutrients ” in nutritional science . But this fact has had little impact on nutrition plans and diets until now.
• Initial studies show that lectins can be linked to rheumatism and Parkinson’s disease .

However, there is (still) a lack of larger studies on the extent to which lectins can promote obesity and illness. However, in a self-experiment, Steven Gundry lost 35 kilograms within a year and at the same time lowered his high blood pressure , and the arthritis had also disappeared.

The doctor treated around 1,000 patients on the basis of these positive experiences with the LFE. He observed 200 of them as part of a study . For six months, the patients who all had cardiovascular diseases such as coronary artery disease ate according to this diet. After completing the examination, her heart function and blood values ​​had improved significantly.

Conclusion: It should definitely not be a fashion diet. However, LFE cannot be easily integrated into everyday life, the usual nutrition plan has to be fundamentally redesigned. But to make this as uncomplicated as possible, the doctor gives many tips and simple to fine recipes in his new guide on “bad vegetables”.