Macro- and Micronutrients

Potatoes are nutrient dense, very low in calories and virtually free of lipids, containing approximately 0.15g/150g fresh weight (FW) in fat. Protein represents about 1-3% of the FW of potatoes and has a high biological value of 90-100 compared with whole egg (100) or soybean (84) ². Patatin is the major storage protein and has been reported to have antioxidant properties. It has been suggested that that the amino acids, cysteine and tryptophan, in patatin might contribute to its free radical scavenging activity³.

Tubers are a good source of Vitamin C, providing 10-13mg/100g or approximately 15% of the recommended daily intake (RDI) for North Americans. Potatoes contain vitamin B6 of 0.3mg (2% of RDI) and as well as the B vitamins, thiamine, riboflavin, and niacin. Potatoes also contain significant amounts of folic acid and could be promoted as a source of this essential nutrient².

Potatoes are an excellent source (approximately 500mg) of potassium(about 25% of the RDI).Excessive dietary sodium (NaCl), in association with a low intake of plant foods which are the major sources of dietary potassium, is an increasing problem in Western diets and may lead to acid-base disorders and to calcium (Ca) and magnesium (Mg) wasting. Narcy et al. have evaluated the effects of potato, rich in potassium citrate, on acid–base homeostasis and mineral retention in Wistar rats⁴.  Wheat starch (WS) or cooked potato (CP) diets were fed in diets with a low (0·5 %) or a high (2%) NaCl content. Urinary Ca and Mg was much higher following the high-salt WS diet (17% and 62% of the daily absorbed mineral) compared with 5% and 28% in rats fed the high-salt CP diet (respectively for both). Ca and Mg intestinal absorption was significantly enhanced following the CP diet (Ca from 39% to 56 %; Mg from 37% to 60%). Thus, the rats fed cooked potato were better able to retain calcium and magnesium in the background of a high salt diet. Diets rich in potassium are known to lower blood pressure in humans and also counter the blood pressure-raising effects of sodium⁵.

Other minerals present include phosphorus (70mg) and calcium (6-18mg) at about 6% of the RDI for both. Potatoes contain little phosphorus as phytate which can form unabsorbable complexes with minerals such as zinc and iron. According to Camire et al., the bioavailability for zinc and iron from potatoes will be higher than in other plant foods with higher phytic acid content².

Antioxidants

Potatoes also contain a variety of phytonutrients that have antioxidant activity. Antioxidants are a powerful group of nutritional compounds that can protect against age related disease through their ability to scavenge free radicals that arise from oxidative processes in the body. Research has shown that an aqueous extract of potato peel (PPE) is rich in various phenolic acids ranging from 2.9 to 4.2mg/g PPE⁶. These phenolic acids have been characterized as gallic acid, caffeic acid, chlorogenic acid and protocatechuic acid.

Chlorogenic acid is the primary phenolic compound found in potatoes. In vitroanalyses using FeSO4 and ascorbic acid to induce lipid peroxidation in rat red blood cells (RBC) and human RBC membranes, showed that PPE inhibited lipid peroxidation with similar effectiveness in both the systems (80-85% inhibition by PPE at 2.5mg/ml)⁷.  The use of scanning electron microscopy demonstrated that PPE significantly protected rat RBC against H2O2-induced morphological changes. Additionally, PPE inhibited oxidative damage induced by the catalyst ferrous-ascorbate in human erythrocyte membrane proteins. These results indicate that PPE is a strong antioxidant capable of protecting erythrocytes against oxidative damage.

An extract from purple potato (EPP) has also been assessed for protection against D-galactosamine (GalN)-induced hepatoxicity in rats⁸. EPP (400mg) significantly reduced markers of liver injury including serum tumor necrosis factor alpha, lactate dehydrogenase, alanine aminotransferase and asparate aminotranferase. As well, lipid peroxide levels in hepatic microsomal cells were significantly lower in the EPP group, suggesting that this potato extract provides hepatoprotective effects via inhibition lipid peroxidation and/or inflammation.

Hypercholesterolemic rats fed 300g of medium purple, dark purple or white potato flakes experienced significantly lower thiobarbituric acid reactive substance (TBARS) levels in serum and liver, and antioxidant enzyme activities in the liver⁹. At this dosage, TBARS levels in the serum and liver of the purple potato groups were significantly lower than those in the control and white potato groups. These results show that modulation of antioxidant enzymes and oxidative status in the serum and liver by the purple potato flake diet and to a more limited extent, the white potato diet, containing polyphenols/anthocyanins may play an important role in the protection against adverse effects related to oxidative damage.

As noted, anthocyanin pigments are found in the skin and flesh of certain varieties of potatoes, the level of which is related to their antioxidant properties. Red and purple potatoes contain the highest levels of anthocyanins¹⁰.  Carotenoids and xanthophylls, lipid-soluble pigments are also found in potatoes¹¹. Carotenoid content ranges from 57-750μg/150g FW, being higher in yellow than white varieties. Carotenoid levels can be increased through breeding efforts¹⁰.

Although found in low levels, the lutein in potatoes but can serve as an important dietary source especially in the elderly. Lutein, an oxygenated xanthophyll, reduces the risk of age related macular degeneration, the leading cause of visual impairment and blindness in older adults.

Another interesting group of phytochemicals found in potatoes are the kukoamines, spermine conjugates with dihydrocaffeic acid¹².  Members of this family show inhibitory activity on soybean lipoxygenase (LOX) and lipid peroxidation. The reducing properties of the compounds were evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay and found to be in the range 5-97.5%¹³. These compounds may also help to lower blood pressure¹⁴. These results are preliminary but if confirmed in clinical studies, may have important consequences for human health.

More recent research has focused on the role that white-skinned sweet potato extract may play in  improving insulin sensitivity in patients with type 2 diabetes mellitus (T2DM)¹⁵. In a randomized trial, 27 patients with T2DM on diet only received 4g of the extract (trade name, Caiapo) daily for five months, while 34 patients received a placebo. The treatment resulted in significant improvements in oral glucose insulin sensitivity and plasma adiponectin.  A decline in fibrinogen associated with improvements in glycated haemoglobin, fasting glucose and triglyceride levels were also reported following the potato extract treatment. This study suggests that a white potato extract has beneficial effects on glucose and HbA1c control and may improve insulin sensitivity.

This latter research confirms  previous studies by these investigators who also reported the beneficial effects of white-skinned sweet potato extract (Caiapo) on fasting plasma glucose, as well as on total and low-density lipoprotein (LDL) cholesterol in T2DM¹⁶. A short-term treatment of six weeks with 4g/d of the extract consistently improved metabolic control T2DM patients by decreasing insulin resistance without affecting body weight, glucose effectiveness, or insulin dynamics. No side effects related to the treatment were observed.

With the rising incidence of obesity and overweight in the North American population, novel dietary supplements are being developed to assist with satiety and reduce food intake. Dietary proteins and trypsin inhibitors are known to stimulate the secretion of the satiety hormone cholecystokinin (CCK). A potato extract (Potein) containing 60% carbohydrate and 20% protein including trypsin inhibitory proteins was examined in rats¹⁷. The extract was found to suppress food intake and directly stimulate CCK secretion in enteroendocrine cells in a dose-dependent fashion.

The anti-obesity and anti-inflammatory effects of an extract of purple sweet potatoes (PSP) on 3T3-L1 adipocytes have also been recently reported¹⁸. 3T3-L1 adipocytes were treated with a PSP extract at concentrations of 1,000, 2,000, and 3,000μg/mL for 24 hours. The PSP extract diminished leptin secretion, indicating that growth of fat droplets was suppressed. The extract also reduced the expression of mRNAs of lipogenic and inflammatory factors and promoted lipolytic action. In addition, the anti-oxidative activity of the PSP extract was confirmed in this research.

Proteinase Inhibitor II (PI2), a protein naturally found in white potatoes is commercially available (trade name, Slendesta) for weight loss applications. PI2 has been reported to enhance the release of CCK which induces satiety. At a 1.5g dose before a meal, P12 reduced energy intake in healthy subjects¹⁹, while an average 2kg weight loss was demonstrated in overweight women when P12 was taken daily prior to lunch and dinner for four weeks²⁰.

An open-label non-randomized clinical study demonstrated statistically significant reductions in weight and body dimensions in overweight and obese adults over a 12-week period, followed by an additional eight weeks of 15-30mg P12 treatment as 300-600mg Slendesta potato extract 5% powder²¹. Subjects lost an average of 4.8kg (10.7lbs) by 16 weeks and 5.3kg (11.7lbs) by 20 weeks. The percentage of subjects losing ≥5% of body weight was 13% by week 4, 30% by week 8, and 53% by week 12 through the end of the study. Reductions of 16% and 9% in waistline and hip dimensions, respectively, were found by 20 weeks. Subjects reported that the P12 treatment made them feel full sooner and longer, made it easier to eat less, and to reduce between-meal snacking throughout the study.

A subsequent randomized, double-blind, placebo-controlled study was conducted with 196 healthy male and female volunteers of an average age of 47 years (ranging from 18-65 years) and a body mass index within 25-35 kg/m² .²² Subjects were randomly assigned to placebo, 15mg, or 30mg P12 treatments consumed 60 minutes prior to the two largest meals daily for 12 weeks. The two P12 treatment groups lost weight in a dose-dependent manner at 12 weeks (0.57kg and 0.64kg, respectively). This weight loss occurred without restricting energy intake or increasing physical activity. A greater weight loss may be achieved with a longer treatment period and/or with restricted diet and exercise. Further, subjects in the 15mg and 30mg dose groups experienced significant waistline reduction of 0.71cm and 0.86cm from baseline at weeks 8 and 12, respectively.

The results of this study indicate that P12 (tested in the commercial product, Slendesta) offers a useful approach to satiety and can be a safe and effective tool for weight loss, and for maintaining weight loss, as part of a weight management program.

As new research demonstrates, potatoes appear to have potential as a functional food and even as a source of valuable healthy bioactive ingredients. However, most people eat potatoes in the form of French fries or potato chips. Baked potatoes are typically loaded down with fats such as butter, sour cream, melted cheese and bacon bits, making even baked potatoes a potential contributor to CVD, T2DM and weight issues. Remove the extra fat and deep frying, and potato can be a healthy, low-calorie, high-fiber food. Research is revealing potential protective effects of potato bioactives against cardiovascular disease as well as to assist in weight loss and management through enhancing satiety.

References:

^1.        Agriculture and Agri-Food Canada 2010. Canadian Potato Situation and Trends 2009–2010. Horticulture and Special Crops Division, Food Value Chain Bureau, Markets.

^2.        Camire, M.E., S. Kubow and D.J. Donnelly. 2009. “Potatoes and Human Health.” Crit. Rev. Food Sci. Nutr. 49(10). 823 – 840.

^3.        Liu, Y.W., C.H. Han and M.H. Lee. 2003. “Patatin, the Tuber Storage Protein of Potato (Solanum tuberosum L.) Exhibits Antioxidant Activity in Vitro.” J. Agric. Food Chem.  51, 4389-4393.

^4.        Narcy, A., L. Robert, A. Mazur,  et al. 2006. “Effect of Potato on Acid-base and Mineral Homeostasis in Rats Fed a High-sodium Chloride Diet.” Br. J. Nutr. 95: 925-932.

^5.        Lin P.H., M. Aickin, C. Champagne, et al. 2003. “Food Group Sources of Nutrients in the Dietary Patterns of the DASH-Sodium trial.” J. Am. Diet. Assoc 103:488–496.

^6.        Singh, N. And P.S. Rajini. 2004. “Free Radical Scavenging Activity of an Aqueous Extract of Potato Peel.” Food Chem. 85: 611-616.

^7.        Singh, N. and P.S. Rajini. 2008. “Antioxidant-mediated Protective Effects of Potato Peel Extract in Erythrocytes Against Oxidative Damage.” Chemico-Biol. Interact. 173: 97-104.

^8.        Han, K.H., N. Hashimoto, K/ Shimada, et al. 2006. “Hepatoprotective Effects of Purple Potato Extract Against D-Galactosamine-induced Liver Injury in Rats.” Biosci. Biotech. Biochem. 70(6). 1432-1437.

^9.        Han, K.H., A. Matsumoto, K. Shimada. 2007. “Effects of Anthocyanin-rich Purple Potato Flakes on Antioxidant Status in F344 Rats Fed a Cholesterol-rich Diet.” Br. J. Nutr. 98, 914–921.

^10.     Brown, C.R. 2008. “Breeding for Phytonutrient Enhancement of Potato.” Am. J. Potato Res. 85: 298-307..

^11.     Breithaupt D.E. and A. Bamedi. 2002. “Carotenoids and Carotenoid Esters in Potatoes (Solanum tuberosum L.): New Insights into an Ancient Vegetable.” J. Agric. Food Chem. 20;50(24):7175-81.

^12.     Parr, A.J., F.A. Mellon, I.J. Colquhoun and H.V. Davies. 2005. “Dihydrocaffeoyl Polyamines (Kukoamine and Allies) in Potato (Solanum tuberosum) Tubers Detected During Metabolite Profiling.” J. Agric. Food Chem.53(13):5461–5466.

^13.     Hadjipavlou-Litina, D., T. Garnelis, C.M. Athanassopoulos, D. Papaioannou, et al. 2009. “Kukoamine A Analogs with lipoxygenase Inhibitory Activity." J. Enzyme Inhibit. Med. Chem. 24(5):1188-1193.

^14.     Ponasik, J.A., et al. 1995.”Kukoamine A and Other Hydrophobic Acylpolyamines: Potent and Selective Inhibitors of Crithidia Fasciculata Trypanothione Reductase.” Biochem. J. 311(Pt 2): 371–375.

^15.     Ludvik B., M. Hanefeld, and G. Pacini. 2008. “Improved Metabolic Control by Ipomoea Batatas (Caiapo) is Associated with Increased Adiponectin and Decreased Fibrinogen Levels in Type 2 Diabetic Subjects.” DiabetesObes. Metab.10(7):586-92.

^16.     Ludvik B., W. Waldhäusl, R. Prager., et al. 2003. “Mode of Action of Ipomoea Batatas (Caiapo) in Type 2 Diabetic Patients.” Metabolism. 52(7):875-80.

^17.     Nakajima S., T. Hira, M. Tsubata, et al. 2011. “Potato Extract (Potein) Suppresses Food Intake in Rats Through Inhibition of Luminal Trypsin Activity and Direct Stimulation of Cholecystokinin Secretion from Enteroendocrine Cells.” J. Agric. Food Chem.14;59(17):9491-6.

^18.     Ju J.H., H.S. Yoon, H.J. Park, et al. 2011. “Anti-obesity and Antioxidative Effects of Purple Sweet Potato Extract in 3T3-L1 Adipocytes in Vitro.” J.Med.Food.14(10):1097-106.

^19.     Hill, A.J., S.R. Peikin, A. Clarence, C.A. Ryan and J.E. Blundell. 1990. “Oral Administration of Proteinase Inhibitor II from Potatoes Reduces Energy Intake in Man.” Physiol. Behavior. 48:241-6.

^20.     Spiegel, T.A., C. Hubert, S.R. Peiken. 1999. “Effect of a Premeal Beverage Containing  Proteinase Inhibitor from Potatoes on Satiety in Dieting Overweight Women” (poster). Presented at the North American Assc for the Study of Obesity Annual Meeting.

^21.     Dana, S. 2005. “An Open Label Clinical Trial to Evaluate a Satiety Aid for Weight Loss in Overweight to Obese, Healthy Adults (Koslow Trial, Phase 1).” Kemin Health White paper.

^22.     Hu, J., B. Edmonson, A. Shao and U.J. Radosevich. 2004. “A Randomized, Double-blind, Single Center Study to Evaluate the Efficacy of a Satiety Aid 1.” Kemin Health White paper.

 Potatoes are astarchy tuberous plant from the perennial Solanum tuberosum of the Solanaceae family (also known as the nightshades). Potatoes are the world's fourth largest food crop, following rice, wheat and maize¹  and globally are the third largest carbohydrate food source.

Macro- and Micronutrients

Potatoes are nutrient dense, very low in calories and virtually free of lipids, containing approximately 0.15g/150g fresh weight (FW) in fat. Protein represents about 1-3% of the FW of potatoes and has a high biological value of 90-100 compared with whole egg (100) or soybean (84) ². Patatin is the major storage protein and has been reported to have antioxidant properties. It has been suggested that that the amino acids, cysteine and tryptophan, in patatin might contribute to its free radical scavenging activity³.

Tubers are a good source of Vitamin C, providing 10-13mg/100g or approximately 15% of the recommended daily intake (RDI) for North Americans. Potatoes contain vitamin B6 of 0.3mg (2% of RDI) and as well as the B vitamins, thiamine, riboflavin, and niacin. Potatoes also contain significant amounts of folic acid and could be promoted as a source of this essential nutrient².

Potatoes are an excellent source (approximately 500mg) of potassium(about 25% of the RDI).Excessive dietary sodium (NaCl), in association with a low intake of plant foods which are the major sources of dietary potassium, is an increasing problem in Western diets and may lead to acid-base disorders and to calcium (Ca) and magnesium (Mg) wasting. Narcy et al. have evaluated the effects of potato, rich in potassium citrate, on acid–base homeostasis and mineral retention in Wistar rats⁴.  Wheat starch (WS) or cooked potato (CP) diets were fed in diets with a low (0·5 %) or a high (2%) NaCl content. Urinary Ca and Mg was much higher following the high-salt WS diet (17% and 62% of the daily absorbed mineral) compared with 5% and 28% in rats fed the high-salt CP diet (respectively for both). Ca and Mg intestinal absorption was significantly enhanced following the CP diet (Ca from 39% to 56 %; Mg from 37% to 60%). Thus, the rats fed cooked potato were better able to retain calcium and magnesium in the background of a high salt diet. Diets rich in potassium are known to lower blood pressure in humans and also counter the blood pressure-raising effects of sodium⁵.

Other minerals present include phosphorus (70mg) and calcium (6-18mg) at about 6% of the RDI for both. Potatoes contain little phosphorus as phytate which can form unabsorbable complexes with minerals such as zinc and iron. According to Camire et al., the bioavailability for zinc and iron from potatoes will be higher than in other plant foods with higher phytic acid content².

Antioxidants

Potatoes also contain a variety of phytonutrients that have antioxidant activity. Antioxidants are a powerful group of nutritional compounds that can protect against age related disease through their ability to scavenge free radicals that arise from oxidative processes in the body. Research has shown that an aqueous extract of potato peel (PPE) is rich in various phenolic acids ranging from 2.9 to 4.2mg/g PPE⁶. These phenolic acids have been characterized as gallic acid, caffeic acid, chlorogenic acid and protocatechuic acid.

Chlorogenic acid is the primary phenolic compound found in potatoes. In vitroanalyses using FeSO4 and ascorbic acid to induce lipid peroxidation in rat red blood cells (RBC) and human RBC membranes, showed that PPE inhibited lipid peroxidation with similar effectiveness in both the systems (80-85% inhibition by PPE at 2.5mg/ml)⁷.  The use of scanning electron microscopy demonstrated that PPE significantly protected rat RBC against H2O2-induced morphological changes. Additionally, PPE inhibited oxidative damage induced by the catalyst ferrous-ascorbate in human erythrocyte membrane proteins. These results indicate that PPE is a strong antioxidant capable of protecting erythrocytes against oxidative damage.

An extract from purple potato (EPP) has also been assessed for protection against D-galactosamine (GalN)-induced hepatoxicity in rats⁸. EPP (400mg) significantly reduced markers of liver injury including serum tumor necrosis factor alpha, lactate dehydrogenase, alanine aminotransferase and asparate aminotranferase. As well, lipid peroxide levels in hepatic microsomal cells were significantly lower in the EPP group, suggesting that this potato extract provides hepatoprotective effects via inhibition lipid peroxidation and/or inflammation.

Hypercholesterolemic rats fed 300g of medium purple, dark purple or white potato flakes experienced significantly lower thiobarbituric acid reactive substance (TBARS) levels in serum and liver, and antioxidant enzyme activities in the liver⁹. At this dosage, TBARS levels in the serum and liver of the purple potato groups were significantly lower than those in the control and white potato groups. These results show that modulation of antioxidant enzymes and oxidative status in the serum and liver by the purple potato flake diet and to a more limited extent, the white potato diet, containing polyphenols/anthocyanins may play an important role in the protection against adverse effects related to oxidative damage.

As noted, anthocyanin pigments are found in the skin and flesh of certain varieties of potatoes, the level of which is related to their antioxidant properties. Red and purple potatoes contain the highest levels of anthocyanins¹⁰.  Carotenoids and xanthophylls, lipid-soluble pigments are also found in potatoes¹¹. Carotenoid content ranges from 57-750μg/150g FW, being higher in yellow than white varieties. Carotenoid levels can be increased through breeding efforts¹⁰.

Although found in low levels, the lutein in potatoes but can serve as an important dietary source especially in the elderly. Lutein, an oxygenated xanthophyll, reduces the risk of age related macular degeneration, the leading cause of visual impairment and blindness in older adults.

Another interesting group of phytochemicals found in potatoes are the kukoamines, spermine conjugates with dihydrocaffeic acid¹².  Members of this family show inhibitory activity on soybean lipoxygenase (LOX) and lipid peroxidation. The reducing properties of the compounds were evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay and found to be in the range 5-97.5%¹³. These compounds may also help to lower blood pressure¹⁴. These results are preliminary but if confirmed in clinical studies, may have important consequences for human health.

More recent research has focused on the role that white-skinned sweet potato extract may play in  improving insulin sensitivity in patients with type 2 diabetes mellitus (T2DM)¹⁵. In a randomized trial, 27 patients with T2DM on diet only received 4g of the extract (trade name, Caiapo) daily for five months, while 34 patients received a placebo. The treatment resulted in significant improvements in oral glucose insulin sensitivity and plasma adiponectin.  A decline in fibrinogen associated with improvements in glycated haemoglobin, fasting glucose and triglyceride levels were also reported following the potato extract treatment. This study suggests that a white potato extract has beneficial effects on glucose and HbA1c control and may improve insulin sensitivity.

This latter research confirms  previous studies by these investigators who also reported the beneficial effects of white-skinned sweet potato extract (Caiapo) on fasting plasma glucose, as well as on total and low-density lipoprotein (LDL) cholesterol in T2DM¹⁶. A short-term treatment of six weeks with 4g/d of the extract consistently improved metabolic control T2DM patients by decreasing insulin resistance without affecting body weight, glucose effectiveness, or insulin dynamics. No side effects related to the treatment were observed.

With the rising incidence of obesity and overweight in the North American population, novel dietary supplements are being developed to assist with satiety and reduce food intake. Dietary proteins and trypsin inhibitors are known to stimulate the secretion of the satiety hormone cholecystokinin (CCK). A potato extract (Potein) containing 60% carbohydrate and 20% protein including trypsin inhibitory proteins was examined in rats¹⁷. The extract was found to suppress food intake and directly stimulate CCK secretion in enteroendocrine cells in a dose-dependent fashion.

The anti-obesity and anti-inflammatory effects of an extract of purple sweet potatoes (PSP) on 3T3-L1 adipocytes have also been recently reported¹⁸. 3T3-L1 adipocytes were treated with a PSP extract at concentrations of 1,000, 2,000, and 3,000μg/mL for 24 hours. The PSP extract diminished leptin secretion, indicating that growth of fat droplets was suppressed. The extract also reduced the expression of mRNAs of lipogenic and inflammatory factors and promoted lipolytic action. In addition, the anti-oxidative activity of the PSP extract was confirmed in this research.

Proteinase Inhibitor II (PI2), a protein naturally found in white potatoes is commercially available (trade name, Slendesta) for weight loss applications. PI2 has been reported to enhance the release of CCK which induces satiety. At a 1.5g dose before a meal, P12 reduced energy intake in healthy subjects¹⁹, while an average 2kg weight loss was demonstrated in overweight women when P12 was taken daily prior to lunch and dinner for four weeks²⁰.

An open-label non-randomized clinical study demonstrated statistically significant reductions in weight and body dimensions in overweight and obese adults over a 12-week period, followed by an additional eight weeks of 15-30mg P12 treatment as 300-600mg Slendesta potato extract 5% powder²¹. Subjects lost an average of 4.8kg (10.7lbs) by 16 weeks and 5.3kg (11.7lbs) by 20 weeks. The percentage of subjects losing ≥5% of body weight was 13% by week 4, 30% by week 8, and 53% by week 12 through the end of the study. Reductions of 16% and 9% in waistline and hip dimensions, respectively, were found by 20 weeks. Subjects reported that the P12 treatment made them feel full sooner and longer, made it easier to eat less, and to reduce between-meal snacking throughout the study.

A subsequent randomized, double-blind, placebo-controlled study was conducted with 196 healthy male and female volunteers of an average age of 47 years (ranging from 18-65 years) and a body mass index within 25-35 kg/m² .²² Subjects were randomly assigned to placebo, 15mg, or 30mg P12 treatments consumed 60 minutes prior to the two largest meals daily for 12 weeks. The two P12 treatment groups lost weight in a dose-dependent manner at 12 weeks (0.57kg and 0.64kg, respectively). This weight loss occurred without restricting energy intake or increasing physical activity. A greater weight loss may be achieved with a longer treatment period and/or with restricted diet and exercise. Further, subjects in the 15mg and 30mg dose groups experienced significant waistline reduction of 0.71cm and 0.86cm from baseline at weeks 8 and 12, respectively.

The results of this study indicate that P12 (tested in the commercial product, Slendesta) offers a useful approach to satiety and can be a safe and effective tool for weight loss, and for maintaining weight loss, as part of a weight management program.

As new research demonstrates, potatoes appear to have potential as a functional food and even as a source of valuable healthy bioactive ingredients. However, most people eat potatoes in the form of French fries or potato chips. Baked potatoes are typically loaded down with fats such as butter, sour cream, melted cheese and bacon bits, making even baked potatoes a potential contributor to CVD, T2DM and weight issues. Remove the extra fat and deep frying, and potato can be a healthy, low-calorie, high-fiber food. Research is revealing potential protective effects of potato bioactives against cardiovascular disease as well as to assist in weight loss and management through enhancing satiety.

References:

^1.        Agriculture and Agri-Food Canada 2010. Canadian Potato Situation and Trends 2009–2010. Horticulture and Special Crops Division, Food Value Chain Bureau, Markets.

^2.        Camire, M.E., S. Kubow and D.J. Donnelly. 2009. “Potatoes and Human Health.” Crit. Rev. Food Sci. Nutr. 49(10). 823 – 840.

^3.        Liu, Y.W., C.H. Han and M.H. Lee. 2003. “Patatin, the Tuber Storage Protein of Potato (Solanum tuberosum L.) Exhibits Antioxidant Activity in Vitro.” J. Agric. Food Chem.  51, 4389-4393.

^4.        Narcy, A., L. Robert, A. Mazur,  et al. 2006. “Effect of Potato on Acid-base and Mineral Homeostasis in Rats Fed a High-sodium Chloride Diet.” Br. J. Nutr. 95: 925-932.

^5.        Lin P.H., M. Aickin, C. Champagne, et al. 2003. “Food Group Sources of Nutrients in the Dietary Patterns of the DASH-Sodium trial.” J. Am. Diet. Assoc 103:488–496.

^6.        Singh, N. And P.S. Rajini. 2004. “Free Radical Scavenging Activity of an Aqueous Extract of Potato Peel.” Food Chem. 85: 611-616.

^7.        Singh, N. and P.S. Rajini. 2008. “Antioxidant-mediated Protective Effects of Potato Peel Extract in Erythrocytes Against Oxidative Damage.” Chemico-Biol. Interact. 173: 97-104.

^8.        Han, K.H., N. Hashimoto, K/ Shimada, et al. 2006. “Hepatoprotective Effects of Purple Potato Extract Against D-Galactosamine-induced Liver Injury in Rats.” Biosci. Biotech. Biochem. 70(6). 1432-1437.

^9.        Han, K.H., A. Matsumoto, K. Shimada. 2007. “Effects of Anthocyanin-rich Purple Potato Flakes on Antioxidant Status in F344 Rats Fed a Cholesterol-rich Diet.” Br. J. Nutr. 98, 914–921.

^10.     Brown, C.R. 2008. “Breeding for Phytonutrient Enhancement of Potato.” Am. J. Potato Res. 85: 298-307..

^11.     Breithaupt D.E. and A. Bamedi. 2002. “Carotenoids and Carotenoid Esters in Potatoes (Solanum tuberosum L.): New Insights into an Ancient Vegetable.” J. Agric. Food Chem. 20;50(24):7175-81.

^12.     Parr, A.J., F.A. Mellon, I.J. Colquhoun and H.V. Davies. 2005. “Dihydrocaffeoyl Polyamines (Kukoamine and Allies) in Potato (Solanum tuberosum) Tubers Detected During Metabolite Profiling.” J. Agric. Food Chem.53(13):5461–5466.

^13.     Hadjipavlou-Litina, D., T. Garnelis, C.M. Athanassopoulos, D. Papaioannou, et al. 2009. “Kukoamine A Analogs with lipoxygenase Inhibitory Activity." J. Enzyme Inhibit. Med. Chem. 24(5):1188-1193.

^14.     Ponasik, J.A., et al. 1995.”Kukoamine A and Other Hydrophobic Acylpolyamines: Potent and Selective Inhibitors of Crithidia Fasciculata Trypanothione Reductase.” Biochem. J. 311(Pt 2): 371–375.

^15.     Ludvik B., M. Hanefeld, and G. Pacini. 2008. “Improved Metabolic Control by Ipomoea Batatas (Caiapo) is Associated with Increased Adiponectin and Decreased Fibrinogen Levels in Type 2 Diabetic Subjects.” DiabetesObes. Metab.10(7):586-92.

^16.     Ludvik B., W. Waldhäusl, R. Prager., et al. 2003. “Mode of Action of Ipomoea Batatas (Caiapo) in Type 2 Diabetic Patients.” Metabolism. 52(7):875-80.

^17.     Nakajima S., T. Hira, M. Tsubata, et al. 2011. “Potato Extract (Potein) Suppresses Food Intake in Rats Through Inhibition of Luminal Trypsin Activity and Direct Stimulation of Cholecystokinin Secretion from Enteroendocrine Cells.” J. Agric. Food Chem.14;59(17):9491-6.

^18.     Ju J.H., H.S. Yoon, H.J. Park, et al. 2011. “Anti-obesity and Antioxidative Effects of Purple Sweet Potato Extract in 3T3-L1 Adipocytes in Vitro.” J.Med.Food.14(10):1097-106.

^19.     Hill, A.J., S.R. Peikin, A. Clarence, C.A. Ryan and J.E. Blundell. 1990. “Oral Administration of Proteinase Inhibitor II from Potatoes Reduces Energy Intake in Man.” Physiol. Behavior. 48:241-6.

^20.     Spiegel, T.A., C. Hubert, S.R. Peiken. 1999. “Effect of a Premeal Beverage Containing  Proteinase Inhibitor from Potatoes on Satiety in Dieting Overweight Women” (poster). Presented at the North American Assc for the Study of Obesity Annual Meeting.

^21.     Dana, S. 2005. “An Open Label Clinical Trial to Evaluate a Satiety Aid for Weight Loss in Overweight to Obese, Healthy Adults (Koslow Trial, Phase 1).” Kemin Health White paper.

^22.     Hu, J., B. Edmonson, A. Shao and U.J. Radosevich. 2004. “A Randomized, Double-blind, Single Center Study to Evaluate the Efficacy of a Satiety Aid 1.” Kemin Health White paper.