Apple pectin

Apples provide energy and are rich in vitamin C and potassium. Apple pectin is particularly valuable as it has a positive effect on blood lipid levels and can prevent colon cancer. "An apple a day keeps the doctor away", as the saying goes. And an apple a day has a lot more to offer: Like most fruit, apples contain few calories - a medium-sized apple (100 g) contains around 50 kilocalories (kcal) or 210 kilojoules (kJ). The apple consists of 85 percent water and is therefore suitable as a thirst quencher when there is no drink to hand. The average carbohydrate content is around 11 grams per 100 grams of fruit flesh. The body can quickly obtain energy from fructose and glucose, which is why apples are popular with athletes and "brain workers" alike. The fiber content is rather low at 1.5 to 2.3 grams per 100 grams of pulp. However, as most of us like to eat apples frequently, they certainly contribute to meeting our needs. Apple pectin is particularly valuable, as it has a positive effect on blood lipid levels and can prevent colon cancer. In terms of minerals, potassium, which is important for the water balance, nerve and muscle metabolism, is particularly noteworthy. A medium-sized apple covers about 7 percent of the daily requirement.

Pectin (also: pectin) is the main binding component of the cell walls of plants and fruits. Chemically, it is a polysaccharide consisting of a linear chain of linked molecules of galacturonic acid. Sections of the backbone with many side chains are also called "hairy regions", sections with few or small side chains are called "smooth sections". Pectin consists of soluble fiber, which means that it absorbs water and thus takes on a gel-like consistency (8). Pectin has the property of being able to form a gel with sugar. This is why pectin is used together with sugar as a thickening agent in the food industry. A well-known use of pectin is in the production of jams. Most types of fruit contain pectin, but not in sufficient quantities to form a thick jelly when making jam; pectin is therefore added to improve the quality of the jam. Pectin is added to a special sugar that is used to make jams and jellies (gelling sugar). Pectin and sugar form a network structure when heated, but not at room temperature. This is why jam thickens during cooking. The group of fruit varieties that contain enough pectin to form a gel is very small; one example is the quince. Commercially available pectin is made from apple and orange pulp (3).

Nutritional value

Pectin provides only a few nutrients. 30 grams of liquid pectin contain (4)

Kcal: 3
Protein: 0 grams
Fat: 0 gram
Carbohydrates: 1 gram
Dietary fiber: 1 gram

Powdered pectin has a similar nutrient content (5). Neither the liquid form nor the powder form contain significant amounts of vitamins or minerals, and all carbohydrates and calories come from fiber.

Applications

Pectin is primarily used as a thickening agent in cooking and jam making, as mentioned above. However, pectin is also sold as a soluble fiber supplement, often in capsule form. Soluble fiber can help relieve constipation, lower cholesterol and triglyceride levels, improve blood sugar levels and support a healthy weight (6). Last but not least, this fiber is a key component of coatings of some sustained-release medications (7).

Health benefits of pectin

Pectin has a number of potential health benefits. In the following sections we will take a closer look at these and the scientific evidence.

Pectin and diabetes

Although there is evidence that pectin has anti-diabetic properties, the evidence is not clear. It was previously thought that dietary fibers such as pectin could help control blood sugar levels in diabetics. However, this may not be the case. A recent study review concluded that only large amounts of certain dietary fibers such as guar gum can lower blood glucose levels, while less viscous fibers such as pectin are not effective (1, 2). Supplementation with pectin (5 grams twice daily for 3 months) did not affect blood glucose control in 17 diabetic patients. The paper concludes that these results suggest that pectin is not helpful in controlling diabetes (9).

In a study of 12 patients with non-insulin-dependent type 2 diabetes, 20 grams of apple pectin per day for 4 weeks resulted in slower gastric emptying and improved glucose tolerance (the body's response to sugar). However, this slower gastric emptying was not directly associated with improved glucose tolerance (10). In two studies of 76 adults (some with type 2 diabetes, hypertension and gallstones), pectin (5.2 grams and a 0.4 liter drink) slowed gastric emptying but did not alter blood glucose levels (11, 12), In rats with type 2 diabetes, citrus pectin increased glucose tolerance, reduced insulin resistance and blood glucose levels and had a general antidiabetic effect (Akt upregulation and GSK3β downregulation - these two events lower blood glucose levels) (13).

Pectin could support weight management

Pectin consumption for 2 days slowed gastric emptying, making subjects feel fuller for longer and less hungry (15 grams of pectin, 9 obese subjects) (14). In one study, 74 subjects of normal weight fasted overnight for 2 days and were then given orange juice with different doses of pectin (5, 10, 15 and 20 grams). In another study, 10 healthy volunteers were given 3 different meals (fiber-free, one meal with agar and one meal with pectin) for one week. In both studies, pectin at a dose of 5.2 grams led to an increased feeling of satiety and reduced food intake (15, 16). In two other studies, pectin (a 0.4 liter drink and 27 grams per day) did not reduce body weight (60 subjects and 11 subjects) (17, 18).

In human studies, fiber intake has generally been associated with a reduced risk of overweight and obesity. This is believed to be related to the fact that fiber is satiating and that most high-fiber foods provide fewer calories than low-fiber foods such as refined grains (19, 20). In addition, animal studies have shown that pectin supplements promoted weight loss and fat burning in obese rats (21, 22, 23, 24). One study in rats found that pectin promoted satiety and reduced calorie intake to a greater extent than a high-protein diet. Similar studies have noted that pectin increased levels of satiety hormones in mice (25, 26, 27).

Pectin could improve cholesterol levels

A meta-analysis involving a total of 2990 people showed that pectin lowered levels of bad LDL cholesterol and total cholesterol levels, but did not change levels of good HDL cholesterol (28). In 2 clinical trials with patients with high cholesterol levels, a mixture of dietary fibers that included pectin lowered total cholesterol levels and LDL cholesterol levels without affecting HDL cholesterol levels or triglyceride levels. The first study used 15 grams of the fiber blend per day for 6 weeks, while the second study used 20 grams of the fiber blend daily for 15 weeks (29, 30). In another study of 66 subjects with high blood glucose levels, a pectin drink increased levels of good HDL cholesterol (17). In healthy rats fed a high-fat diet, apple pectin lowered total cholesterol levels, LDL cholesterol levels and triglyceride levels (31).

Pectin could lower blood pressure

In a clinical study of 66 subjects with high blood glucose levels, a pectin drink (0.4 liters) reduced systolic blood pressure (17). A meta-analysis looked at the effects of viscous soluble fiber (β-glucan, guar gum, konjac, pectin and psyllium husk) and found that it lowered systolic and diastolic blood pressure (32).

Pectin could reduce the risk of heart disease

Pectin at a dose of 15 grams per day for 4 weeks blocked the formation of blood clots, a risk factor for heart disease, in men with high cholesterol levels (33). Grapefruit pectin supplementation reduced total cholesterol levels and LDL cholesterol levels while improving the ratio of LDL to HDL cholesterol without dietary or lifestyle changes. However, this supplementation had no effect on triglyceride levels, VLDL cholesterol levels and HDL cholesterol levels (34).

Pectin can relieve diarrhea

In 2 studies with children suffering from persistent diarrhea, 4 grams of pectin per kilogram of body weight effectively reduced diarrhea (35, 36). In a study of 86 subjects suffering from irritable bowel syndrome with diarrhea, 24 grams of pectin per day over a period of 6 weeks restored the balance of the intestinal flora and alleviated the symptoms of the disease (37).

Pectin can be helpful for digestive tract problems

As a soluble fiber with unique gel-forming properties, pectin can aid digestion in many ways. Soluble fiber turns to gel in the digestive tract in the presence of water. This softens the stool and speeds up the transit time of food through the digestive tract, which can reduce constipation (38). In addition, many soluble fibers are prebiotics - food sources for the healthy bacteria in the gut (39). It has been shown that pectin by-products (oligosaccharides) blocked the growth of harmful gut bacteria and stimulated the growth of healthy bifidobacteria and lactobacilli (44, 45). In a four-week study of 80 people suffering from constipation, those who consumed 24 grams of pectin daily had larger populations of healthy bacteria in the gut and fewer symptoms of constipation than the control group (40).

In addition, some animal studies have shown that pectin supplements can improve the health of gut bacteria, reduce inflammation and alleviate unwanted symptoms in the digestive tract (25, 41, 42). Furthermore, pectin can form a protective barrier around the inner lining of the gut to prevent harmful bacteria from entering the body (44). In addition to this, pectin may also help with ulcerative colitis (an inflammatory bowel disease). In a study of 20 patients suffering from this disease who received a transplant of fecal bacteria from healthy donors, a dose of 20 grams of pectin per day increased the effectiveness of the transplant and reduced the symptoms of ulcerative colitis (46).

Pectin could reduce vomiting

A rice-based diet with pectin (4 grams per kilogram of body weight for one week) reduced vomiting in 62 boys with diarrhea (48). In a crossover clinical trial, 18 children with cerebral palsy were fed a diet either high or low in pectin. After 4 weeks, the pectin-rich diet reduced vomiting (48).

Pectin could reduce acid reflux

Around 14 to 20% of the population suffer from acid reflux - a condition in which stomach acid leaks into the esophagus. This can lead to heartburn or gastroesophageal reflux if it occurs too frequently (49, 50). In a study of 18 children with cerebral palsy who were tube-fed, fewer and less severe episodes of acid reflux were observed in the children who received pectin (48). However, due to the limited nature of this study, further studies are needed.

Pectin could reduce radiation damage

In southern Russia, the effects of the Chernobyl nuclear accident are still being felt. In a cohort study of 94 children with high to moderate levels of the radioactive element cesium-137, pectin (5 grams of Vitapekt) administered for 16 days reduced radiation damage and levels of the radioactive element (51). In another study, pectin reduced levels of the radioactive element cesium-137 by 62.6% in 64 children exposed to radiation (52).

Pectin could reduce lead poisoning

In 7 children with lead poisoning, pectin (15 grams of PectaSol) significantly reduced high blood lead levels (53). In rats, pectin reduced lead levels in multiple organs (54).

Pectin could reduce cancer

Modified pectin (smaller and less complex pectin molecules) could reduce certain types of cancer. In rats, modified citrus pectin reduced the spread of prostate cancer, but did not reduce primary tumor growth (55). In several cell studies, modified pectin reduced the growth of prostate cancer, colon cancer, melanoma and leukemia cells (56, 57, 58, 59, 60). In test tube studies, pectin was also able to kill colon cancer cells (61, 62). In addition, this dietary fiber helps reduce inflammation and cellular damage that can stimulate the formation of colon cancer cells, which could reduce the risk of colon cancer (63).

Scientists theorized that pectin may reduce colorectal cancer risk by binding with and inhibiting the absorption of galectin-3. High levels of galectin-3 are associated with an increased risk of colorectal cancer (64, 65). Test tube studies have also shown that pectin killed other types of cancer cells including breast cancer cells, liver cancer cells, gastric cancer cells and lung cancer cells (66, 67, 68). However, further research is needed to better understand if and how pectin can affect cancer in humans.

Pectin could increase iron absorption

There is some research showing that apple pectin may improve iron absorption. Iron is an essential mineral that transports oxygen throughout the body and is a component of red blood cells (69, 70). This could be particularly important for people suffering from anemia - a condition associated with weakness and fatigue caused by iron deficiency. The World Health Organization (WHO) estimates that over 30% of the world's population is anemic (71). Menstruating women and anyone following a vegan or vegetarian diet are at particularly high risk of iron deficiency.

Menstruation can cause iron loss, while iron found in plant-based foods is not absorbed by the human body as well as iron from animal foods (72, 73). However, studies with apple pectin show mixed results. While one study conducted with rats showed that pectin increased iron absorption, another showed no effect in this direction (74, 75). For this reason, further human studies are needed.

Pectin could strengthen skin and hair

Hair loss affects millions of people and is considered difficult to treat (76). Anecdotal evidence links apple pectin to stronger hair and skin. It has even been added to cosmetic products such as shampoo that promise fuller hair (77). However, there is as yet no scientific evidence linking pectin to skin or hair health. The best option is to eat whole apples, as their vitamin C content supports healthy skin (78).

Pectin as a delivery system for medicines

Several studies have found pectin to be an effective nasal spray delivery system for painkillers (fentanyl) (79, 80, 81). A review study concluded that pectin can potentially be used as a carrier for the oral delivery of drug molecules, although this requires further investigation (82).

Limitations

Many clinical studies conducted with pectin used pectin in combination with other dietary fibers, making it difficult to determine the specific effects of pectin. Although many of the studies cited were human studies, they sometimes included only a small number of subjects or were too short in duration.

Foods that are rich in pectin

The highest amounts of pectin are found in the peels of citrus fruits such as oranges, lemons and grapefruit (30 to 35%) and in apple pulp (15 to 20%). Other good sources include quinces, plums, gooseberries, cherries, apricots and carrots (83). Pectin, which is used in the food industry, is extracted from apple pulp or the peel of citrus fruits and used as a gelling agent (for jam and jelly) or as a stabilizer in sweets, fruit juices and milk drinks (84, 85, 82).

Dosage

More studies need to be done to establish the need for apple pectin supplements. People in one study who wanted to achieve a cholesterol-lowering effect took a dose of 5 to 20 grams per day. For diarrhea, ulcerative colitis and constipation, doses ranged from 20 to 24 grams per day. For the prevention of blood clots, 15 grams per day were used. When supplementing with apple pectin, plenty of fluids should be consumed If you want to supplement apple pectin in your diet, you should follow the instructions of the respective product.

Safety and side effects

The use of apple pectin in normal food quantities is considered safe and harmless. The use of apple pectin in medicinal quantities is potentially safe for most people, including children and pregnant and breastfeeding women. When taken orally, pectin on its own in combination with guar gum and insoluble fiber - the combination used to lower cholesterol and other blood lipid levels - can cause side effects such as diarrhea, bloating and loose stools (87).

In addition, people should avoid pectin if they are allergic to the food from which the pectin was made. Most commercial products are made from apples or the peels of citrus fruits. People who are allergic to pistachios and cashews may also be sensitive to pectin (88). People who are exposed to pectin dust, as can be the case when processing pectin, could develop asthma (86).

Interactions

Care should be taken when combining apple pectin with the following medications:

Antibiotics (tetracyline antibiotics)

Apple pectin may reduce the amount of tetracyline antibiotics that the body can absorb. Taking apple pectin in combination with tetracyline antibiotics could reduce the effectiveness of tetracyline antibiotics. To avoid this interaction, apple pectin should be taken two hours before or four hours after taking tetracyline antibiotics.

Statins

Pectin may reduce the absorption of statins, which are used to lower cholesterol levels. In 3 patients with high cholesterol levels, taking 15 grams of pectin and 80 mg of a cholesterol-lowering drug (lovastatin) daily increased LDL cholesterol levels (89).

Digoxin

Pectin reduces the absorption of digoxin (a widely used drug for the treatment of heart failure) and reduces its effect. To prevent this, pectin and digoxin should be taken at least 2 hours apart (90).

Beta-carotene (vitamin A)

In a cross-over design study in which 7 healthy volunteers received 12 grams of pectin with 25 mg of beta-carotene, pectin reduced beta-carotene blood levels by over 50% (91).

Conclusion

Pectin is a soluble dietary fibre with pronounced gelling properties that is often used to thicken and stabilize foods such as jam and jelly. Although pectin has a variety of health benefits, further human studies are needed to fully understand its effects on health.

Eating a wide variety of fruits and vegetables is an excellent way to increase your pectin intake.