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Consuming Konjac Lowers Blood Cholesterol

LDL (low density lipoprotein) cholesterol has been characterised as ‘bad’ cholesterol. On the other hand, HDL (high density lipoprotein) cholesterol has been characterised as ‘good’ cholesterol. Glucomannan has been shown to lower total cholesterol levels as well as LDL cholesterol.

Glucomannan can also lower blood pressure and blood lipids, which are two other key means of lowering cholesterol. Here are some studies that describe these effects.

Study: Baker W, Coleman C, Sood N. “Effect of glucomannan on plasma lipid and glucose concentrations, body weight, and blood pressure: systematic review and meta-analysis” [2]

This study analysed a collection of randomised trials involving glucomannan. Using this collection, the study then summarised glucomannan’s effects, including how glucomannan can be used to manage cholesterol levels.

Results

Across these trials, glucomannan significantly lowered total cholesterol and LDL cholesterol. The weighted mean difference, or average difference, was

  • 19.28 mg/dL; 95% CI: 24.30, 14.26 for total cholesterol

  • 15.99 mg/dL; 95% CI:21.31, 10.67 for LDL cholesterol


Conclusions

Many trials of glucomannan have been shown to significantly lower total cholesterol and LDL cholesterol.

Study: Arvill A, Bodin L. “Effect of short-term ingestion of konjac glucomannan on serum cholesterol in healthy men” [1]

This study investigated the effect of glucomannan on cholesterol levels. 63 healthy men participated in the investigation. These men were encouraged not to make any changes to their diet or lifestyle during the length of the study.

For four weeks, these men were given 3.9 g glucomannan or placebo daily as part of their first treatment. This was followed by a two week washout period, where these men stopped receiving treatment. A crossover then took place. Those who were previously treated with glucomannan were swapped to placebo, and vice versa. This second treatment then went on for four weeks.

Results

After four weeks of treatment, glucomannan reduced

  • total cholesterol concentrations by 10%
  • LDL cholesterol concentrations by 7.2%

  • systolic blood pressure by 2.5%

The ratio of HDL cholesterol to LDL cholesterol did not change significantly.

Conclusions

This study shows that glucomannan can effectively lower total cholesterol and LDL cholesterol in healthy adults. It can also lower systolic blood pressure. This refers to the pressure exerted on blood vessels when the heart pushes blood throughout the body. A low systolic blood pressure also promotes low cholesterol.

The men in this study continued with their usual diets for the duration of the study. These diets were high in fat and low in dietary fibre. A useful future study would be to see whether, combined with a diet high in other fibres like glucomannan, glucomannan could have an even greater effect on cholesterol levels.

Study: Chen H, Sheu WH, Tai T, et al. “Konjac Supplement Alleviated Hypercholesterolemia and Hyperglycemia in Type 2 Diabetic Subjects - A Randomized Double-Blind Trial” [4]

This study investigated the effects of glucomannan on the cholesterol levels of diabetic individuals. These individuals had elevated blood cholesterol levels but were not taking any lipid-lowering medication at the time of the study.

For 28 days, 12 individuals were randomly assigned to take placebo capsules. For the same 28 days, 10 received glucomannan capsules. After these 28 days, those on the glucomannan capsules were switched to the placebo capsules, and vice versa, for another 28 days.

Glucomannan capsules contained

  • 0.5g konjac powder


Placebo capsules contained

  • 0.5g food-grade corn starch


These capsules were taken half an hour before each meal with a glass of water, and three times a day.

The dose of glucomannan was gradually increased during the 28 day period, as follows:

  • 1.2g for 3 days

  • 2.6g for 3 days

  • 3.6g for 22 days


Results

Compared with placebo, glucomannan reduced

  • plasma cholesterol by 11.1%

  • LDL-cholesterol by 20.7%

  • the total cholesterol to HDL cholesterol ratio by 15.6%


Relative to the placebo, glucomannan also increased

  • fecal bile acid content by 75%


Conclusions

Supplementing these diabetic individuals with glucomannan significantly lowered LDL cholesterol. For this reason, it could be an effective way of treating those with diabetes.

Although it is not fully understood, it has been suggested that dietary fibre decreases blood lipid and cholesterol by increasing an output of bile acid. A study by Chandalia et al. [3] has shown that increasing an intake of mainly soluble fiber can significantly decrease cholesterol absorption by 10% in diabetic individuals. At the same time, it can also increase fecal bile acid excretion by 41% in diabetic individuals. This suggests that these two factors, the decrease of cholesterol absorption and the increase of fecal bile acid, are related. However, there have been few studies done on humans that can back this up completely, and this theory only stands strong in animal studies.

In other previous studies of glucomannan, the dose of glucomannan that was used was quite high. This dose was 8g to 13g a day, which is nearly one third of the recommended fibre intake. By using only a maximum of 3.6g of glucomannan, this study shows that glucomannan can be effective at lowering cholesterol even in small doses.

However, the effect of using glucomannan for longer than a month has not been well documented. Nevertheless, this study suggests that glucomannan could be a promising means of effectively lowering cholesterol and blood pressure.

It must also be noted that there is much controversy over whether high cholesterol correlates to a higher risk of heart disease, and whether there are much more effective avenues to reducing this risk. If you are interested in this field, we highly recommended that you watch this documentary.

If you find our information useful, please consider supporting our project by purchasing your Konjac needs from us.

References

1. Arvill A, Bodin L. “Effect of short-term ingestion of konjac glucomannan on serum cholesterol in healthy men”. The American Journal of Clinical Nutrition Vol. 61 No. 3 (1995): 585-589.


2. Baker W, Coleman C, Sood N. “Effect of glucomannan on plasma lipid and glucose concentrations, body weight, and blood pressure: systematic review and meta-analysis”. The American Journal of Clinical Nutrition, Vol. 88 No. 4 (2005): 1167-1175.


3. Chandalia M, Garg A, Lutjohann D, et al. “Beneficial effects of high dietary fiber intake in patients with type 2 diabetes mellitus”. The New England Journal of Medicine Vol. 342 No. 19 (2000): 1392-1398.


4. Chen H, Sheu WH, Tai T, Liaw Y, Chen Y. “Konjac Supplement Alleviated Hypercholesterolemia and Hyperglycemia in Type 2 Diabetic Subjects - A Randomized Double-Blind Trial”. Journal of the American College of Nutrition Vol. 22 No. 1 (2003): 36-42.