Caiapo Sweet Potato (Ipomoea batatas) Shows Beneficial Effects of Improving Insulin Resistance

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The Caiapo sweet potato is a potato variety of the species Ipomoea batatas, and is native to South America, in particular Brazil.  The potato is a white-skinned sweet potato and the dried powder from the potato has been used traditionally as a natural healthy food.

The name Caiapo is dervied from the Kayapo or Caiapó people, a tribe of people that are indigenous to Brazil.   The Caiapó live in the plain islands of the Mato Grosso and Pará in Brazil, south of the Amazon Basin and along Rio Xingu.  1 

Indios Caiapos

There have been a number of studies from 2002 to 2011 that demonstrate the ability of Caiapo (powder) improve glycemic control by reducing insulin resistance.  It is especially beneficial from the conclusion of these studies to reduce fasting blood glucose levels and reduce HbA1c levels.  HbA1c is also known as glycated hemoglobin and is a form of hemoglobin that is measured primarily to identify the average plasma glucose concentration over prolonged periods.

The four of the most important research studies on the benefits of Caiapo are summarized below:

Study 1  (January 2002)

Recently, it has been shown that caiapo, the extract of white-skinned sweet potato (Ipomoea batatas), improves glycemic control in rodents by reducing insulin resistance. The aim of our study was to assess the effect of caiapo on glucose metabolism and its tolerability and mode of action in male Caucasian type 2 diabetic patients in a randomized, double-blind prospective study in parallel groups controlled with placebo.

This pilot study demonstrates that ingestion of 4 g caiapo/day for 6 weeks reduces fasting blood glucose and total as well as LDL cholesterol in male Caucasian type 2 diabetic patients previously treated by diet alone. The improvement of insulin sensitivity in the FSIGT indicates that caiapo exerts its beneficial effects via reducing insulin resistance. The treatment was well tolerated, with no apparent side effects.

Table 1—Metabolic parameters before (upper line) and after (lower line) treatment with caiapo in the single groups

Placebo Low dose High dose
n 6 6 6
Fasting plasma glucose (mmol/l) 8.2 ± 0.2 8.8 ± 0.4 8.3 ± 0.6
8.4 ± 0.3 8.4 ± 1.1 7.2 ± 0.4*
Fasting plasma insulin (pmol/l) 8.7 ± 1.7 8.3 ± 1.6 13.4 ± 2.5
8.7 ± 1.2 9.0 ± 1.8 13.2 ± 2.5
Total cholesterol (mmol/l) 5.69 ± 0.23 6.05 ± 0.31 4.97 ± 0.21
5.66 ± 0.31 5.68 ± 0.34 4.45 ± 0.18*
LDL cholesterol (mmol/l) 3.72 ± 0.23 4.11 ± 0.28 3.12 ± 0.16
3.78 ± 0.41 3.80 ± 0.28 2.72 ± 0.16*
HDL cholesterol (mmol/l) 1.40 ± 0.10 1.27 ± 0.10 1.16 ± 0.05
1.42 ± 0.16 1.16 ± 0.10 1.11 ± 0.05
Triglycerides (mmol/l) 1.26 ± 0.15 1.45 ± 0.35 1.52 ± 0.19
1.37 ± 0.30 1.61 ± 0.30 1.33 ± 0.13
HbA1c (%) 7.0 ± 0.3 7.3 ± 0.4 7.1 ± 0.3
7.0 ± 0.2 7.3 ± 0.4 6.8 ± 0.3
Blood pressure (mmHg) 134 ± 13 147 ± 18 135 ± 20
130 ± 18 133 ± 19 128 ± 21
BMI (kg/m2) 28.9 ± 0.9 25.5 ± 0.8 28.6 ± 1.3
29.2 ± 0.8 25.8 ± 0.9 28.1 ± 1.5

In conclusion, this pilot study shows beneficial effects of high-dose caiapo on plasma glucose and total as well as LDL cholesterol levels in patients with type 2 diabetes. These effects relate to a decrease in insulin resistance, as also described in rodents, and were observed without affecting body weight or causing side effects. Therefore, the results of this pilot study indicate that caiapo could potentially play a role in the treatment of type 2 diabetes.  2 

Study 2  (February 2004)

To investigate the tolerability, efficacy, and mode of action of Caiapo, an extract of white sweet potatoes, on metabolic control in type 2 diabetic patients.

A total of 61 type 2 diabetic patients treated by diet were given 4 g Caiapo (n = 30; mean age 55.2 ± 2.1 years; BMI 28.0 ± 0.4 kg/m2) or placebo (n = 31; mean age 55.6 ± 1.5 years; BMI 27.6 ± 0.3 kg/m2) once daily for 12 weeks. Each subject underwent a 75-g oral glucose tolerance test (OGTT) at baseline and after 1, 2, and 3 months to assess 2-h glucose levels.

After treatment with Caiapo, HbA1c decreased significantly (P < 0.001) from 7.21 ± 0.15 to 6.68 ± 0.14%, whereas it remained unchanged (P = 0.23) in subjects given placebo (7.04 ± 0.17 vs. 7.10 ± 0.19%). Fasting blood glucose levels decreased (P < 0.001) in the Caiapo group (143.7 ± 1.9 vs. 128.5 ± 1.7 mg/dl) and did not change in the placebo group (144.3 ± 1.9 vs. 138.2 ± 2.1 mg/dl; P = 0.052).

This study confirms the beneficial effects of Caiapo on plasma glucose as well as cholesterol levels in patients with type 2 diabetes. For the first time, the long-term efficacy of Caiapo on glucose control was demonstrated by the observed decrease in HbA1c. Thus, the neutraceutical Caiapo seems to be a useful agent in the treatment of type 2 diabetes.   3 

Figure 1—

Figure 1— Changes in fasting glucose concentration in the two treatment groups during the study period. Asterisks indicate significant differences for Caiapo versus placebo (*P < 0.05; **P < 0.001). See results for additional statistics.

Figure 2—

Figure 2— Changes in glucose concentration measured 2 h after a 75-g oral glucose load in the two treatments during the study period. Asterisks indicate significant differences for Caiapo versus placebo (*P < 0.005; **P < 0.001). See results for additional statistics.

Study 3  (July 2008)

The extract of the white-skinned sweet potato Ipomoea batatas (Caiapo) has been shown to ameliorate glucose control by improving insulin sensitivity in patients with type 2 diabetes mellitus (T2DM). The present study was designed to further evaluate its mode of action on insulin sensitivity over an extended period of time as well as the effects on fibrinogen and other markers of low-grade inflammation.

In this randomized trial, 27 patients with T2DM on diet only received 4 g of Caiapo daily for 5 months; 34 patients placebo. Before and after therapy, insulin sensitivity [oral glucose insulin sensitivity (OGIS), as glucose clearance from oral glucose tolerance test], parameters of diabetes control, lipids, plasma adiponectin, high-sensitivity C-reactive protein (hs-CRP) and fibrinogen were measured.

This study confirms the beneficial effects of Caiapo on glucose and HbA1c control in patients with T2DM after 5 months follow-up. Improvement of insulin sensitivity was accompanied by increased levels of adiponectin and a decrease in fibrinogen. Thus, Caiapo can be considered as natural insulin sensitizer with potential antiatherogenic properties.  4 

Study 4 (March 2011)

Caiapo sweet potato has been found to contain arabinogalactan proteins.  A study from March 2011 examined the effects of an arabinogalactan protein (WSSP-AGP) from Ipomoea batatas L. on hyperglycemia in db/db mice.

An oral glucose tolerance test indicated significantly decreased plasma glucose levels by WSSP-AGP.  Additionally, an insulin tolerance test found improvement in insulin sensitivity due to treatment with WSSP-AGP.

The study’s conclusion suggests that amelioration of insulin resistance by WSSP-AGP causes to lead its hypoglycemic effects.  5 


Informational References:

Fuji-Sangyo Co., Ltd. – Caiapo Potato Powder


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