White kidney bean extract is promoted as a starch blocker and weight-loss aid. Manufacturers say that it curbs hunger and cravings, inhibits carbohydrate absorption and reduces abdominal fat. While it's true that kidney beans may aid in weight loss, supplements don't have the same effect.
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The research on white kidney bean extract is limited. Kidney beans are a lot more nutritious and have proven health benefits. Rich in protein, fiber and bioactive compounds, these legumes increase satiety, kick-start your metabolism and keep you full for hours. Weight-loss supplements, on the other hand, are subject to debate and lack scientific proof.
What Is Kidney Bean Extract?
Weight loss is a billion dollar industry. Thousands of products are now available on store shelves, from fat burners to appetite suppressants and prescription diet pills. Unfortunately, most supplements lack scientific proof and carry serious side effects. If they worked, obesity wouldn't be a global epidemic.
There are various types of diet pills and each has a different mechanism of action. White kidney bean extract is marketed as a starch neutralizer or carb blocker. This product comes in pill form and claims to reduce or inhibit the absorption of carbs, including sugars and starches.
Read more: The 10 Best Supplements
As its name suggests, this supplement is extracted from white kidney beans, or common beans (Phaseolus vulgaris). Proponents say that phaseolamin, a naturally occurring glycoprotein in these legumes, inhibits alpha-amylase, a pancreatic enzyme that aids in starch digestion.
According to a review published in Current Obesity Reports in April 2016, phaseolamin is clinically proven to reduce glucose absorption when used in doses ranging from 1.5 to 6 grams per day. However, more research is needed to confirm its effects.
Does It Work?
One of the few human studies showing a relationship between white kidney bean extract and weight loss was published in the International Journal of Medical Sciences in January 2007 and has been frequently cited in subsequent studies so it still appears to be relevant.
Overweight men and women who took a supplement containing Phaseolus vulgaris extract daily before a high-carb meal experienced a greater reduction in fat mass, waist and hips circumference, body mass index and other obesity markers compared to the control group. Surprisingly, they maintained lean body mass despite losing weight. This supplement appears to be safe.
Other studies have involved only animals, so their results are not necessarily relevant to humans, but it is of interest to consider them. For example, a research article published in the April 2019 edition of the Journal of Nutrition and Metabolism reviewed the effects of white kidney bean extract on rat adipose tissue. As the researchers note, this supplement increases lipolysis, or fat breakdown, when used in large doses.
Other studies cited in the above review showed that white kidney bean extract may reduce body mass, increase satiety and improve blood lipids in animals. Furthermore, it lowers postprandial blood sugar levels, reducing fat storage. This legume also contains lectins, a group of proteins that bind to carbohydrates. These compounds decrease insulin levels and prevent your body from storing fat.
Despite their potential benefits, lectins are considered anti-nutrients. According to the Harvard T.H. Chan School of Public Health, these proteins may cause digestive discomfort and inhibit nutrient absorption. However, they also protect your cells from oxidative stress and prevent blood sugar spikes by slowing down carbohydrate absorption. The consumption of lectin-containing foods has been linked to a lower risk of obesity, heart disease and metabolic disorders.
The studies featured in the Journal of Nutrition and Metabolism suggest that certain antioxidants in beans may facilitate weight loss. These bioactive compounds inhibit the formation of new fat cells and stimulate fat breakdown.
White Kidney Beans Nutrition Facts
As you see, the effectiveness of white kidney bean extract is subject to debate. Most researchers agree, though, that beans are a healthy addition to any diet.
For example, a June 2013 meta-analysis published in PLOS One has linked the consumption of legumes, including beans, to a lower risk of colorectal cancer. The lectin in white kidney beans may kill cancer cells and stop them from spreading throughout the body.
These legumes are chock-full of fiber, protein, iron, potassium and other essential nutrients. One serving (a half cup) of cooked kidney beans has only 112 calories and provides about 23 percent of the daily recommended fiber intake. It also contains:
- 7.7 grams of protein
- 0.4 grams of fat
- 20.2 grams of carbs
- 5.7 grams of fiber
- 0.3 grams of sugars
- 21 percent of the DV (daily value) of copper
- 17 percent of the DV of manganese
- 11 percent of the DV of iron
- 9 percent of the DV of magnesium
- 8 percent of the DV of potassium
- 8 percent of the DV of zinc
- 6 percent of the DV of vitamin K
Beans are loaded with folate, thiamin, choline and other B-complex vitamins. They also contain bioactive compounds, such as saponins, polyphenols, flavonoids and phenolic acids, as reported in a review posted in the journal Molecules in August 2017.
Saponins, for example, protect against heart disease, inflammation and cancer, according to the Molecules review. These compounds strengthen your immune system, reduce blood sugar and cholesterol levels, prevent cavities and fight oxidative stress. The polyphenols in white kidney beans are associated with lower rates of cardiovascular problems, type 2 diabetes and neurodegenerative diseases. Flavonoids keep your heart healthy and may reduce the risk of lung cancer.
Kidney Beans Suppress Hunger
Whether you want to get leaner or clean up your diet, kidney beans are a great choice. Dietary fiber, one of the most abundant nutrients in beans, makes it easier to maintain your weight and protects against chronic illnesses.
According to a meta-analysis published in the North American Journal of Medicine and Science in April 2015, this nutrient may lower all-cause mortality. Researchers have found that it may decrease heart disease risk by 23 percent, cancer risk by 17 percent and inflammatory disease risk by 43 percent. High-fiber intakes were associated with a 23 percent lower risk of death from all causes.
Furthermore, a diet rich in fiber may protect against digestive disorders. At the same time, fiber facilitates weight loss by increasing satiety. You've probably noticed that beans, chickpeas, kale, spinach and other high-fiber foods fill you up quickly and make it easier to stick to your diet. By adding beans to your meals, you'll stay full longer and eat less without feeling hungry or deprived.
Kidney beans also boast large doses of protein, making them ideal for vegans, vegetarians and dieters. High-protein foods not only curb hunger but also help you build and preserve lean mass when combined with an exercise plan. Protein increases your metabolic rate too, leading to more calories burned throughout the day.
On top of that, beans are simply delicious. Try healthy white kidney beans recipes like spinach and white bean soup, grilled chicken breast with white bean salad and avocado, white bean chili, marinated bean salad jars or white bean hummus with roasted garlic. It's a simple, convenient way to boost your daily intake of fiber and protein. A diet rich in legumes, leafy greens, fresh fruit, fish, lean meat and other whole foods is more effective than any weight-loss pill.
- Current Obesity Reports: "New Dietary Supplements for Obesity: What We Currently Know"
- Journal of Nutrition and Metabolism: "Effects of Phaseolus vulgaris Extract on Lipolytic Activity and Differentiation of 3T3-L1 Preadipocytes Into Mature Adipocytes: A Strategy to Prevent Obesity"
- Diapedia: "Lipolysis and Lipogenesis"
- Harvard T.H. Chan School of Public Health: "Lectins"
- PLOS One: "Legume Consumption and Colorectal Adenoma Risk: A Meta-Analysis of Observational Studies"
- ScienceDirect: "White Kidney Bean Lectin Exerts Anti-Proliferative and Apoptotic Effects on Cancer Cells"
- USDA: "Nutrition Facts for Kidney Beans"
- MDPI: Molecules: "Bioactive Compounds From Mexican Varieties of the Common Bean (Phaseolus vulgaris): Implications for Health"
- North American Journal of Medicine and Science: "Dietary Fiber Intake and Mortality from All Causes, Cardiovascular Disease, Cancer, Infectious Diseases and Others: A Meta-Analysis of 42 Prospective Cohort Studies With 1,752,848 Participants"
- Joslin Diabetes Center: "How Does Fiber Affect Blood Glucose Levels?"
- British Journal of Nutrition: "Dietary Protein – Its Role in Satiety, Energetics, Weight Loss and Health"
- International Journal of Obesity: "The Role of Higher Protein Diets in Weight Control and Obesity-Related Comorbidities"
- NCBI: International Journal of Medical Sciences: "A Dietary Supplement Containing Standardized Phaseolus vulgaris Extract Influences Body Composition of Overweight Men and Women"