52
and up to 42% in triglyceride levels suggesting RS to be more effective in lowering
blood lipids than synthetic drugs like cholestyramine (Younes et al. 1995). A study
conducted by Cheng and Lai (2000) found a marginal decreasing effect of rice resistant starch on serum cholesterol as well as hepatic cholesterol of animal subjects
compared to control receiving corn starch. The researchers ascribed this effect to the
increase in propionate levels formed as result of fermentation of rice resistant starch
with its major effect in lowering hepatic cholesterol. A study conducted by So et al.
(2007) investigating the beneficial effect of RS on lowering of blood lipids subjected mice to dietary interventions wherein one group was fed with diet containing
high resistant starch content and vice versa. A reduced fat deposition, serum lipids
and plasma leptons were found in the subjects fed with high RS diet. Conclusion
were drawn suggesting a possible link between the fermentation of RS leading to
SCFA production and protein receptors involved in adipocyte differentiation and
proliferation has been sought to be the possible mechanism. Even though RS has
been found to be very much beneficial in reducing lipids, the consumption of RS in
healthy individuals is yet controversial. Different studies conducted by Stewart
et al. (2010) and Heijnen et al. (1996) didn’t find any remarkable effect of RS consumption on the reduction of serum cholesterol and adipose fat deposition whereas
earlier Behall et al. (1989) found a noteworthy decrease in blood lipids and total fat
content on the consumption of RS. Mathe et al. (1993) with their studies on obese
rats found RS efficient in decreasing serum cholesterol. Zhou et al. (2015) found a
direct influence of RS consumption on the enhanced population of gut micro flora
that undoubtly increased the SCFA levels inhibiting the biosynthesis of cholesterol.
Similarly, in another human study, resistant starch type 4 (RS4) consumption
improved dyslipidemia and body composition that resulted in 7.2% lower mean
total cholesterol, 5.5% lower non-HDL, and 12.8% lower HDL cholesterol in individuals with metabolic syndrome (Nichenametla et al. 2014). In a study on animals,
the rats were fed with diets supplemented with RS (raw potato starch and high
amylose corn starch) to study the effects on ceacal digestion and lipid metabolism
in comparison with rats adapted to semi purified diets. The results showed significant ceacal hypertrophy (240% after 7 day of the fiber consumption) and shortchain fatty acids accumulation (especially propionic and butyric acids) in rats fed
with RS diets. Apart from this the cholesterol absorption was reduced to 14% of
intake in rats fed with resistant starch enriched diets compared with 47% absorption
in control rats. RS diets were also effective in lowering plasma cholesterol (−31 and
−27%, respectively) and triglycerides (−28 and −22%, respectively) (Lopez et al.
2001). In another study on rats, RS diets led to a marked rise in ceacal size and the
ceacal pool of short-chain fatty acids (SCFA), as well as SCFA absorption; cholestyramine did not noticeably affect ceacal fermentation while on the other hand
cholestyramine was particularly effective at enhancing bile acid excretion. RS was
more effective in lowering plasma cholesterol (−32%) and triglycerides (−29%). In
rats fed the RS diet, there was a lower concentration of cholesterol in all lipoprotein
fractions, especially the fraction high-density lipoprotein (HDL), while those fed
cholestyramine had only a significant reduction of HDL cholesterol. In contrast to
cholestyramine, RS also depressed the concentration of triglycerides in the
G. Akhtar et al.
and up to 42% in triglyceride levels suggesting RS to be more effective in lowering
blood lipids than synthetic drugs like cholestyramine (Younes et al. 1995). A study
conducted by Cheng and Lai (2000) found a marginal decreasing effect of rice resistant starch on serum cholesterol as well as hepatic cholesterol of animal subjects
compared to control receiving corn starch. The researchers ascribed this effect to the
increase in propionate levels formed as result of fermentation of rice resistant starch
with its major effect in lowering hepatic cholesterol. A study conducted by So et al.
(2007) investigating the beneficial effect of RS on lowering of blood lipids subjected mice to dietary interventions wherein one group was fed with diet containing
high resistant starch content and vice versa. A reduced fat deposition, serum lipids
and plasma leptons were found in the subjects fed with high RS diet. Conclusion
were drawn suggesting a possible link between the fermentation of RS leading to
SCFA production and protein receptors involved in adipocyte differentiation and
proliferation has been sought to be the possible mechanism. Even though RS has
been found to be very much beneficial in reducing lipids, the consumption of RS in
healthy individuals is yet controversial. Different studies conducted by Stewart
et al. (2010) and Heijnen et al. (1996) didn’t find any remarkable effect of RS consumption on the reduction of serum cholesterol and adipose fat deposition whereas
earlier Behall et al. (1989) found a noteworthy decrease in blood lipids and total fat
content on the consumption of RS. Mathe et al. (1993) with their studies on obese
rats found RS efficient in decreasing serum cholesterol. Zhou et al. (2015) found a
direct influence of RS consumption on the enhanced population of gut micro flora
that undoubtly increased the SCFA levels inhibiting the biosynthesis of cholesterol.
Similarly, in another human study, resistant starch type 4 (RS4) consumption
improved dyslipidemia and body composition that resulted in 7.2% lower mean
total cholesterol, 5.5% lower non-HDL, and 12.8% lower HDL cholesterol in individuals with metabolic syndrome (Nichenametla et al. 2014). In a study on animals,
the rats were fed with diets supplemented with RS (raw potato starch and high
amylose corn starch) to study the effects on ceacal digestion and lipid metabolism
in comparison with rats adapted to semi purified diets. The results showed significant ceacal hypertrophy (240% after 7 day of the fiber consumption) and shortchain fatty acids accumulation (especially propionic and butyric acids) in rats fed
with RS diets. Apart from this the cholesterol absorption was reduced to 14% of
intake in rats fed with resistant starch enriched diets compared with 47% absorption
in control rats. RS diets were also effective in lowering plasma cholesterol (−31 and
−27%, respectively) and triglycerides (−28 and −22%, respectively) (Lopez et al.
2001). In another study on rats, RS diets led to a marked rise in ceacal size and the
ceacal pool of short-chain fatty acids (SCFA), as well as SCFA absorption; cholestyramine did not noticeably affect ceacal fermentation while on the other hand
cholestyramine was particularly effective at enhancing bile acid excretion. RS was
more effective in lowering plasma cholesterol (−32%) and triglycerides (−29%). In
rats fed the RS diet, there was a lower concentration of cholesterol in all lipoprotein
fractions, especially the fraction high-density lipoprotein (HDL), while those fed
cholestyramine had only a significant reduction of HDL cholesterol. In contrast to
cholestyramine, RS also depressed the concentration of triglycerides in the
G. Akhtar et al.