Pecans are especially rich in one form of vitamin E gamma tocopherol. An increased level of gamma tocopherol concentrations in the blood subsequently reduces a marker of lipid oxidation (Haddad, et al. , 2006). Xianli Wu et al. , (2004) reported that pecans rank highest among all nuts and are among the top category of foods to contain the highest total anti-oxidant capacity (TCA). It is observed that 28. 4 g (1 oz) of pecans had 5,095 TAC (Vegparadise News Bureau, 2004), and a dietary fiber 9. 00 g/100 g (Feldman, 2002).
Plant sterols, widely researched and touted for their cholesterol-lowering ability are found naturally in pecans. They contain as much as 95 milligrams of plant sterols per 100 grams 90 percent of which is in the form of beta-sitosterol. Beta-sitosterol as a food component that competes with the absorption of cholesterol in the body, and thus has the ability to lower blood cholesterol levels. By increasing consumption of pecans (or peanuts), a person could easily raise the plant sterol levels in the diet to the point where health effects have been proven (Eitenmiller, 2000).
Haddad, et al. , (2006) reported that the pecan-enriched diets significantly reduced lipid oxidation (by 7. 4 percent) versus the Step I diet, and the blood levels of tocopherols were higher after participants were on the pecan diet. Cholesterol-adjusted plasma gamma-tocopherol in the study participants blood samples increased by 10. 1 percent (P < . 001) after eating the pecan diet. Another key research finding was beyond the reduced level of blood lipid oxidation, the various phytochemicals found in pecans seem to be protective of the pecans high levels of unsaturated fat.
All unsaturated fats in foods can be prone to oxidation themselves (which some may describe in foods as rancidity). Pecans, while high in unsaturated fat, are self-protective due to their vitamin E content (tocopherols) and relatively high content of complex phytonutrients, some of which have been identified as proanthocyanidins, or condensed tannins, which are recognized for their ability to slow the oxidation process. Diets that are high in monounsaturated fat (MUFA) have been associated with reducing the risk of cardiovascular disease.
According to this scientific statement from AHAs Nutrition Committee, there is epidemiological evidence that dietary monounsaturated fats (MUFAs) have a beneficial effect on the risk of (CHD). Kris-Etherton et al. , 1999 from epidemiological studies concluded, there is consistent evidence, that nuts have a strong protective effect against coronary heart disease (CHD). From the of clinical database studies it is evident that the cardio protective effect of nuts is due to their favorable effects on plasma lipids and lipoproteins, owing to their fatty acid composition when they replace dietary saturated fat and/or carbohydrates.
Rajaram et al. , (2001) reported the effects of a pecan-rich diet on serum lipids and lipoproteins in 23 normocholesterolemic males and females. After a run-in period of 2 weeks on a typical American diet, subjects were fed for 4 weeks either the pecan diet or a Step 1 diet in a randomized, controlled, crossover design. The pecan diet was higher in total fat (42 vs. 30%); both diets had 8% long chain saturated fatty acid whereas the pecan diet was higher in MUFA (24 vs. 15%) and PUFA (10 vs. 7%).
The pecan diet significantly lowered total cholesterol (11. 3% compared with 5. 2% on the Step I diet) and LDL cholesterol (16. 5% compared with 6. 7% on the Step I diet). In fact, the pecans doubled the cholesterol lowering ability of the Step I diet. The pecan diet increased HDL cholesterol levels whereas the Step I diet decreased HDL unfavorably. Triglycerides also were significantly lower with the pecan diet. Although the pecan diet contained more fat (39. 6%) than the Step I diet (28. 3%), participants did not gain weight.
Haddad et al. (2001) studied evaluated effects of a pecan-enriched diet on serum gamma tocopherol levels by using blood samples from the same research participants studied by Rajaram et al (2001). From the data it was concluded that the pecan-enriched diet significantly raised blood levels of gamma tocopherol compared to the AHA Step I diet. This is due to the high amounts of naturally occurring gamma tocopherol (a unique form of vitamin E) in the pecans. The gamma tocopherol-to-cholesterol ratio was higher on the pecan-enriched diet compared to the control diet.
According to Dr. Haddad, gamma tocopherol is an important antioxidant nutrient. Studies have shown that it may benefit intestinal health and have a protective effect against prostate cancer. They also observed that the pecan diet increased stool fat excretion. Stools were collected for 48 h in six subjects during each of the diet periods. Stool fat (25 g pecan, 6 g Step 1) and the percentage of fat in the stool (8% pecan, 3% Step 1) increased significantly with the pecan diet. These changes may explain, in part, why the added fat or calories in a nut-based diet do not lead to weight gain.
The pecan fat may not have been as well-absorbed because of the structure of lipid-storing granules in nuts or the fiber components of the nuts. Researchers at Texas A&M University discovered that a heart-healthy diet containing pecans can help control specific biomarkers of heart disease risk as effectively as the AHA Step I diet. Jessica Barloon et al. , (2001) observed significantly increased levels of dietary fiber, thiamin, magnesium, copper and manganese in the participants by studying forty hypercholesterolemic men and women between the ages of 22 and 71, all of whom had already been eating a relatively low-fat diet.
During the eight-week, randomized, controlled feeding trial, participants were placed on either the AHA Step I diet or an isocaloric but higher-fat, pecan-based diet. the pecan-rich diet significantly increased participants levels of dietary fiber, thiamin, magnesium, copper and manganese and actually changed dietary copper and magnesium intakes from inadequate (on the AHA diet) to adequate (on the pecan diet). An epidemiological study of food intake and health outcomes of 34,492 post-menopausal Iowa women conducted by Yochum et al. , (2000) evaluated the relationship between antioxidant vitamins intake and stroke.
The researchers found that death from stroke was 60 percent lower among those consuming the most vitamin E from foods when compared to those who consumed the least. These findings are of particular importance as the Recommended Daily Intake (RDI) for vitamin E was recently raised for both men and women. This population research suggest that eating foods like pecans which are rich in a number of healthy nutrients, including vitamin E helps increase levels of vitamin E in the diet. The higher intakes of vitamin E from foods (compared with lower intake from foods) may be associated with a lower risk of death from stroke.
Vitamin E is a free radical scavenger and thus may help prevent oxidation of LDL, an important step in the atherosclerotic process. Pecans are included in the American governments newest dietary guidelines because of their high concentration of important nutrients and proteins(Dietary Guidelines for Americans, 2005). The monounsaturated fat in pecan is not only protective against heart disease but also controls diabetes (Franz et al. , 2002). Thus intake of pecans reduces the risk factors and provides good health.