Lipid metabolism and antioxidant status in sucrose vs. potato-fed rats.

OBJECTIVE: Consumption of high levels of simple carbohydrates is associated with several metabolic disorders in humans and in laboratory animals, including symptoms of an early stage of metabolic syndrome (syndrome X). This disorder has several cardiovascular risk factors, such as hypertriglyceridemia, and is associated with an increase in oxidative stress. In contrast to sucrose, potato, a source of complex carbohydrates and antioxidant micronutrients, was thought to improve lipid metabolism and antioxidant protection. METHODS: We investigated the effects of diets containing i) complex dietary carbohydrates and antioxidant micronutrients (potato Solanum tuberosum L.), ii) complex carbohydrates (starch) and iii) a simple carbohydrate (sucrose) on lipid metabolism and antioxidant status in rats. RESULTS: An increase in short chain fatty acid (SCFA) pools was observed in the cecum of rats fed a potato-based diet, resulting from an increase in all SCFAs, especially propionate (+360%, P < 0.0001). Feeding rats a potato-based diet for 3 weeks led to a decrease in cholesterol (-37%, potato vs. control and -32%, potato vs. sucrose) and triglycerides (-31%, potato vs. control and -43%, potato vs. sucrose) concentrations in triglyceride-rich lipoproteins (TGRLP) fractions. The antioxidant status was decreased by sucrose consumption and improved by potato consumption. CONCLUSIONS: Our present results suggest that consumption of complex carbohydrates (provided as cooked potatoes), in combination with different antioxidant micronutrients, may enhance the antioxidant defences and improve lipid metabolism, when compared with starch (complex carbohydrates) and to sucrose consumption (source of simple sugar). These effects limit oxidative stress and reduce the risk of developing the associated degenerative diseases, including cardiovascular disease, and could have potential in cardiovascular disease prevention.

Effect of potato on acid-base and mineral homeostasis in rats fed a high-sodium chloride diet.

Excessive dietary NaCl in association with a paucity of plant foods, major sources of K alkaline salts, is a common feature in Western eating habits which may lead to acid-base disorders and to Ca and Mg wasting. In this context, to evaluate the effects of potato, rich in potassium citrate, on acid-base homeostasis and mineral retention, Wistar rats were fed wheat starch (WS) or cooked potato (CP) diets with a low (0.5 %) or a high (2 %) NaCl content during 3 weeks. The replacement of WS by CP in the diets resulted in a significant urinary alkalinisation (pH from 5.5 to 7.3) parallel to a rise in citrate and K excretion. Urinary Ca and Mg elimination represented respectively 17 and 62 % of the daily absorbed mineral in rats fed the high-salt WS diet compared with 5 and 28 % in rats fed the high-salt CP diet. The total SCFA concentration in the caecum was 3-fold higher in rats fed the CP diets compared with rats fed the WS diets, and it led to a significant rise in Ca and Mg intestinal absorption (Ca from 39 to 56 %; Mg from 37 to 60 %). The present model of low-grade metabolic acidosis indicates that CP may be effective in alkalinising urine, enhancing citrate excretion and ameliorating Ca and Mg balance.

Entire potato consumption improves lipid metabolism and antioxidant status in cholesterol-fed rat.

BACKGROUND: Vegetables and fruits are rich sources of a variety of nutrients, including vitamins (E and C), trace minerals, and dietary fibers, and many other classes of biologically active compounds such as carotenoids and polyphenols, which are often assumed to protect against degenerative pathologies such as cardiovascular diseases. Although potato is considered as a starchy food, it is also included in the category of vegetables by its micronutrient content. AIM OF THE STUDY: In the present study, we investigated in the rat the effect of a potato-enriched diet on lipid metabolism and antioxidant protection. RESULTS: Feeding rats a potato-enriched diet for 3 weeks led to a significant decrease in cholesterol and triglyceride levels in plasma (respectively, -30%, P<0.0001 and -36%, P<0.05) and cholesterol level in liver (-42%, P<0.0001). Antioxidant status was also improved by potato consumption. TBARS levels in heart were decreased and vitamin E/triglycerides ratio in plasma was improved. CONCLUSIONS: Our present results suggest that consumption of cooked potatoes (consumed with skin) may enhance antioxidant defense and improve the lipid metabolism. These effects could be interesting for prevention of cardiovascular disease.