Dates are the fruits of the date palm tree (Phoenix dactylifera). The tree itself is similar in appearance to the coconut palm, with mature tree reaching a height of around 30 meters. Date are an important Worldwide food and may be one of the oldest agricultural crops. Records suggest that dates have been harvested for around 8000 years. In particular the date is an important crop in the Middle East, where the date is part of the traditional diets of local populations. One of the advantage of dates over other crops is that although they are harvested in the autumn, they store well and so are available all year round. The amount of dates produced by the date palm trees is immense, with clusters of dates weighing up to 10 kg, and each tree containing multiple clusters. Because the trees can live for eighty years or more, and bear fruit after about year 5, it can be seen how economically important dates are as a fruit crop. Around 75 % of the World’s dates are grown in the Middle East, although California, Texas and Arizona also contribute significantly.
Nutritionally dates are very interesting. The carbohydrate content of dates is high, as they contain around 60 to 70 percent sugar. The predominant sugars in dates are sucrose and fructose, as is common in most fruits. However, while the sugar content is high the total energy in a single date only amounts to roughly 20 to 25 kcals. The high carbohydrate content may be seen as a disadvantage, based on the negative connotations associated with sugar. However, dates also contain considerable amounts of fibre, and this improves the glycaemic profile considerably. In fact dates are not associated with negative effects from the sugars, and this likely relates to both the high fibre content and the high levels of certain vitamins, particularly of B vitamins including niacin, folate, pyridoxine, thiamine and pantothenic acid. In addition minerals such as copper, zinc, selenium, potassium, manganese and magnesium can also accumulate in dates, depending on the soil conditions on which the palms are grown.
The fibre in dates is a beta-D-glucan fibre that may have particular health benefits. One physiological effects that beta-D-Glucan fibre has been shown to possess is one of limiting cholesterol absorption. Studies using oats for example have shown beneficial lipid lowering effects, a factor that has been attributed to the soluble beta-D-glucan fibre they contain. However, as oats possess other components that can lower blood cholesterol this is controversial. Beta-D-Glucan can for example limit the rate at which glucose is absorbed. This produces beneficial glycaemic effects that may improve insulin sensitivity, and this decrease metabolic dysfunction, particularly in the liver, that can include detrimental changes to blood lipid levels. The presence of beta-D-glucan fibre may make dates an effective weight loss food, as has been shown for oats. Dates are also rich in antioxidants and this may be another route by which dates provide important health benefits.