Glycemic Index of Bread: Fiber or Minerals? This is the Question.
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 96
- 主要终点
- AUC of serum glucose
研究概览
简要总结
Glycemic index (GI) of food is known to be positively associated with the development of several diseases including type 2 diabetes, cardiovascular disease and age-related macular degeneration. Modest dietary changes from high-GI foods to low-GI foods have shown beneficial effects. These findings have been translated to recommendations for increased dietary intake of whole grains. However, the inverse relationship between whole grain consumption and risk of the different components of metabolic syndrome has not been explained by their fiber content. Trials of added cereal fiber have failed to induce a protective effect and fiber has thus been proposed to be a marker of other components of whole grains that impart health advantages. Whole wheat grains are known to be a rich source of several minerals (phosphorus, potassium and magnesium) that play a role in glucose metabolism, and are depleted during the process of refinement. Thus, it is plausible to hypothesize that the benefits of whole grains previously ascribed to their fiber content are in fact due to these minerals. The proposed research aims to restore or fortify white bread with these minerals and determine the resulting glycemic index of mineral-fortified bread. With much evidence that most people prefer the taste and color of white bread, a low GI, mineral fortified white bread has the potential to reduce the risk of Metabolic Syndrome in those who consume it.
详细描述
The production of white flour requires the milling of the wheat grain and extraction of a proportion of the grains. The level of 80% extraction is the most-commonly used in the production of white flour in the market and this process leads to a substantial loss of vitamins and minerals (Table 1). These vitamins and minerals are known to affect energy metabolism. For example, thiamin is known to affect carbohydrate metabolism and low thiamin intake is known to cause Beriberi. This has led to the establishment of an acceptable carbohydrate and energy: thiamin ratio (0.4mg of thiamin/1000 kcal) and many countries are fortifying their white wheat flour with thiamin to sustain an acceptable ratio. Although several minerals are known to affect energy and carbohydrate metabolism no clear ratio has been put in place yet.
Table 1: the effect of milling on mineral content of wheat flour Mineral content Wheat flour (white) Wheat flour (whole grain) Loss (%) Phosphorus (mg/100g) 108 346 69 Potassium (mg/100g) 107 408 74 Magnesium (mg/100g) 22 138 84
Specific Aim 1: Determine the acceptability of mineral fortified white bread. White flour will be supplemented with minerals to produce mineral-fortified bread. The acceptability of the bread will be tested.
White wheat flour (80% extraction) will be fortified with minerals. Potassium phosphate will be used as the source of phosphorus and potassium to fortify white flour. From previous experience, the addition of potassium phosphate to glucose solution was found to minimally affect the organoleptic properties. Unlike that of sodium phosphate that was not well tolerated by subjects due to development of unfavorable flavor (fishy flavor). At the same time, magnesium chloride will be used as the source of magnesium. Magnesium chloride is known to be highly soluble and is commonly used as a supplement or fortificant.
Locally produced white wheat flour (80% extraction) and whole grain wheat flour will be purchased and stored at the department. White and whole flour samples (n=3) will be analyzed for their content of phosphorus, magnesium and potassium according to standard procedures
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Basic Science
- 盲法
- Single (Participant)
入排标准
- 年龄范围
- 18 Years 至 45 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Healthy subjects
排除标准
- •any disease, pregnant and lactating
结局指标
主要结局
AUC of serum glucose
时间窗: two hours
次要结局
未报告次要终点
研究者
Omar Obeid
Professor
American University of Beirut Medical Center