Introduction
The date palm (Phoenix dactylifera L.) tree is one of the oldest trees that have been cultivated since the dawn of agriculture [1], and its fruits possess a substantial number of nutritional and functional constituents [2-4]. The nutritional composition of DPFs certainly relies upon their cultivar and ripening stage. The main constituents of DPFs are carbohydrates in the form of glucose, fructose, and Non Starch Polysaccharides (NSPs) [2,5]. Although there is a high content of simple sugars, the quality of carbohydrates in DPFs, which has been determined by the Glycaemic Index (GI), has shown that most date varieties have low GI values [5-9]. Moreover, DPFs are rich in minerals such as potassium, sodium, and magnesium [2]. However, the concentrations of water and fat soluble vitamins in DPFs were found to be low. Additionally, DPFs possess small quantities of protein and fat [2,3]. In addition, DPFs exhibit considerable quantities of biologically active molecules [10,11]. The contents of these bioactive compounds in DPFs vary significantly based on several factors, such as date palm cultivars, the stage of fruit development, post harvest processing, soil conditions, and geographical location [1,10-12].
In fact, the bioactive compounds in DPFs exhibit antioxidant activity as well as antimicrobial and antimutagenic properties. The antioxidant activity in DPFs was found to be high [13]. This characteristic of DPF substances plays a crucial role in the prevention of oxidative stress damage in the human body because DPF constituents act as free radical scavengers [1,10,12,14]. Studies have shown that high consumption of fruits is associated with a low incidence of chronic degenerative diseases [15]. However, DPF is still one of the underexploited healthy fruits [16]. This review explores the importance of DPFs as an excellent source of nutrients and functional constituents, with an emphasis on the beneficial health effects of DPF constituents on the human body.
Quantity Verse Quality of Carbohydrates in Date Palm Fruits
Carbohydrates are the predominant constituents in DPFs, and the carbohydrate content reaches 53 gm/100 gm FW (fresh weight) in the Rutab stage (partially ripened stage of DPF) and 73 gm/100 gm FW in the Tamer stage(fully ripened stage) [2]. The main carbohydrates in DPFs are monosaccharides, which consist of glucose (23-30%) and fructose (19-28%), and NSPs (7-10%) [2,5]. A recent study has found that consuming approximately 100 gm of DPFs results in the intake of approximately, 11%, 16%, and 24% of the daily Recommended Dietary Allowances (RDA) of energy, simple carbohydrates, and NSPs, respectively [17].
The Glycaemic and Insulinaemic Indices of Date Palm Fruits
The assessment of the quality of carbohydrates, which is measured by the GI value, has shown that most DPFs have a low GI value [5-9]. The average GI value of more than 30 cultivars of DPFs was approximately 53 [Table/Fig-1] [5,6,8,9,18-22]. The low GI value of most DPFs is attributed to the presence of considerable quantities of fructose and NSPs [2]. The inverse correlation between the GI value and the fructose has been reported [18]. Moreover, the GI value can be further reduced by consuming DPFs with yoghurt, yoghurt drinks, or nuts [Table/Fig-2] [5-9,18-22]. On the other hand, the blood glucose response to dates was modestly increased when the dates were consumed with Arabic coffee [6]. However, one study found that drinking Arabic coffee did not adversely affect the blood glucose response to dates [20].
Total carbohydrates (CHOs), available carbohydrates, glycaemic index (GI) and glycaemic load (GL) values, and glycaemic index and glycaemic load levels of date palm fruits at the Tamer stage.
| Dates varieties | Total CHO | Available CHO | Available CHO in serving size | GI value | GI level | GL value | GL level |
|---|
| Ajwah, Qassim, Saudi [8] | 71.3 | 61.3 | 16.4 | 56 | medium | 9 | low |
| Birhi (mean of two studies) [8,21] | 72.8 | 57.3 | 15.4 | 56 | medium | 9 | low |
| Bo ma’an (mean of two studies) [9,22] | 74.0 | 64.0 | 17.2 | 38 | low | 7 | low |
| Dabbas, UAE [9] | 70.8 | 68.4 | 18.4 | 49 | low | 9 | low |
| Deglet Noor, Algeria [5] | 84.1 | 70.9 | 19.1 | 52 | low | 10 | low |
| Fardh (mean of two studies) [9,18] | 68.1 | 61.4 | 16.5 | 53 | low | 9 | low |
| H’mira, Algeria [5] | 72.2 | 58.4 | 15.7 | 48 | low | 8 | low |
| Khalas (mean of six studies) [6,9,18-20,22] | 70.2 | 64.2 | 17.3 | 48 | low | 8 | low |
| Khasab, Oman [18] | 67.2 | 54.8 | 14.8 | 55 | low | 8 | low |
| Khudhary (mean of two studies) [8,21] | 74.5 | 61.3 | 16.5 | 59 | medium | 10 | low |
| Lulu, UAE [9] | 70.8 | 69.0 | 18.6 | 53 | low | 10 | low |
| Maktoomi, Qassim, Saudi [8] | 72.9 | 61.3 | 16.5 | 71 | high | 12 | medium |
| Medjool, Qassim, Saudi [8] | 70.9 | 61.3 | 16.5 | 55 | low | 9 | low |
| Nabtat-ali, Qassim, Saudi [8] | 72.2 | 61.3 | 16.5 | 60 | medium | 10 | low |
| Nabtat-seif, Qassim, Saudi [8] | 74.6 | 61.3 | 16.5 | 54 | low | 9 | low |
| Nabut Seif, Riyadh, Saudi [21] | 69.9 | 61.3 | 16.5 | 64 | medium | 11 | medium |
| Nabut Sultan, Riyadh, Saudi [21] | 69.9 | 61.3 | 16.5 | 51 | low | 8 | low |
| Osilah, Qassim, Saudi [8] | 60.6 | 53.5 | 14.4 | 56 | medium | 8 | low |
| Rabiea, Riyadh, Saudi [21] | 69.9 | 61.3 | 16.5 | 55 | low | 9 | low |
| Rashodia, Qassim, Saudi [8] | 74.3 | 61.3 | 16.5 | 51 | low | 8 | low |
| Ruthana (mean of two studies) [8,21] | 69.0 | 61.3 | 16.5 | 53 | low | 9 | low |
| Sabaka, Qassim, Saudi [8] | 71.9 | 61.3 | 16.5 | 55 | low | 9 | low |
| Saqai (mean of two studies) [8,21] | 69.3 | 61.3 | 16.5 | 51 | low | 8 | low |
| Sellaj (mean of two studies) [8,21] | 71.2 | 61.3 | 16.5 | 65 | medium | 11 | medium |
| Shaqra, Qassim, Saudi [8] | 74.7 | 61.3 | 16.5 | 43 | low | 7 | low |
| Shishi, Qassim, Saudi [8] | 69.6 | 61.3 | 16.5 | 50 | low | 8 | low |
| Sukkary (mean of two studies) [8,21] | 67.1 | 61.3 | 16.5 | 45 | low | 7 | low |
| Tinnisine, Algeria [5] | 68.6 | 56.1 | 15.1 | 44 | low | 7 | low |
| Um-Kabar, Qassim, Saudi [8] | 72.3 | 61.3 | 16.5 | 58 | medium | 10 | low |
| Wannanah, Qassim, Saudi [8] | 74.0 | 61.3 | 16.5 | 51 | low | 8 | low |
Total available carbohydrates (CHOs), glycaemic index (GI) and glycaemic load (GL) values, glycaemic index and glycaemic load levels, and insulinaemic index (II) of date palm fruits at the Rutab and Tamer stages, served with yoghurt and Arabic coffee, and stuffed with nuts.
| Item | Serving size (g) | Available CHOs (g) | GI value | GI level | GL value | GL level | II value |
|---|
| Date palm fruit (Tamer stage) [5,6,8,9,18,21,22] | 27 | 17 | 52 | low | 9 | low | 64 |
| Date palm fruit (Tamer stage, 27 gm) served with 125 gm full fat plain yoghurt [19] | 152 | 24 | 29 | low | 7 | low | |
| Date palm fruit (Rutab stage) [19] | 27 | 12 | 47 | low | 6 | low | |
| Date palm fruit (Rutab stage, 27 gm) served with 125 gm full fat plain yoghurt [19] | 152 | 19 | 37 | low | 7 | low | |
| Date palm fruit (Tamer stage, 27 gm) served with 200 mL Arabic coffee drink [6,20] | 227 | 17 | 58 | medium | 10 | low | 62 |
| Date palm fruit (Tamer stage, 27 gm) stuffed with 12 gm nuts [7] | 39 | 18 | 42 | low | 8 | low | |
Moreover, the Insulinaemic Index (II) of the Khalas date variety at the Tamer stage was determined, and it was found that the consumption of dates has an intermediate impact on the insulinaemic response [Table/Fig-2] [6].
Glycaemic Load of Date Palm Fruits
The amount of carbohydrates in the DPFs and the rate and extent of the digestion of these carbohydrates are determined using Glycaemic Load (GL). The GL was introduced to simultaneously assess the quality and quantity of carbohydrates consumed [23]. The GL value of DPFs was calculated for a serving size of three DPFs (27 gm), and it was found that DPFs have a low GL with an average value of 9 [Table/Fig-2]. This finding confirms the minimal effect of both the quality and quantity of DPF carbohydrates. The GL of DPFs is a good indicator to estimate the overall impact of carbohydrates on the blood glucose response [24]. Both the GI and GL values of DPFs should be taken into account when planning to include DPFs in a diabetic patient’s diet. It has been found that the high consumption of low GL foods was associated with reducing the risk of developing type 2 diabetes [25].
Functional Components in Date Palm Fruits
Bioactive Compound Contents
Bioactive compounds are naturally produced as secondary metabolites and most of them are modulators of metabolic processes; therefore, they are not often required for the daily functioning of living organisms [26]. In DPFs, the bioactive compounds can be classified into two groups: nutritive and non nutritive bioactive compounds. Examples of these two groups and their functional activities are demonstrated in the [Table/Fig-3] [1,2,5,10,11,27-32].
Classification of bioactive compounds in date palm fruits and their functional properties.
| Function | Specific compounds |
|---|
| Bioactive nutritive compounds [2,5,27,30-32] | Inhibiting oxidative activityScavenging free radicalsGastrointestinal activitiesConferring taste | Vitamin C (ascorbic acid)Precursor vitamin A (β-carotene)Precursor vitamin E (α-tocopherol)Soluble NSPs (pectin and β-glucans)Insoluble NSPs (cellulose, hemicellulose, and lignin)Selenium |
| Bioactive non-nutritive compounds [1,2,10,11,27-29] | Inhibiting oxidative activity Scavenging free radicalsConferring taste and color to the date fruits | Phenolic acidsCarotenoidsFlavonoidsPolyphenolsPhytosterols |
Antioxidant Content in Date Palm Fruits
The antioxidant content in DPFs has been extensively studied and was found to be the highest compared to the antioxidant contents of other commonly consumed fruits, such as strawberry, kiwi, guava, white pomegranate, and purple mulberry [13]. In general, the antioxidant activity of DPFs is significantly correlated with their total content of phenolic compounds [33]. However, there are some factors that can influence the activity of the antioxidants in DPFs, including date cultivars, ripening stages, and processing [10,33,34]. In fact, it has been found that the antioxidant activity in the Khalas cultivar was higher than that in the other cultivars [11]. Moreover, the highest antioxidant activity occurs at the Bisir stage of DPF development [Table/Fig-4], and this activity gradually decreases at the Tamer stage [34]. This reflects the inverse relationship between the ripening stage of DPFs and the antioxidant activity [Table/Fig-4], starting from the Bisir stage (earliest stage of ripeness) of DPF development [34]. Additionally, it has been reported that date processing, such as sun drying and storage, caused a reduction in the total antioxidant activity. This reduction is possibly due to enzymatic oxidation or decomposition of natural antioxidants such as the conversion of soluble tannins into insoluble tannins [2,11].
Total glucose, fructose, protein, phenolics concentrations, and antioxidant activity of date fruit during ripening stages.
Reference: Date fruit stages are obtained from Al-Mssallem et al. (2013) [35].
The importance of the antioxidant properties of DPFs in the context of human health will be discussed below.
Nutritional and Functional Health Benefits of Date Palm Fruits
General Health Benefits
The beneficial effects of DPFs on human health are well documented. DPFs play an important role as a source of nutrients and functional ingredients. Interestingly, although DPFs consist mostly of easily absorbed carbohydrates in the form of glucose and fructose, no detrimental effect has been observed on serum glucose or triglycerides when the DPFs have been consumed by healthy subjects [36]. In fact, DPFs are a good source of NSPs, and daily consumption of approximately nine DPFs can contribute approximately one-fourth of the daily RDA of NSPs [17,37]. The NSPs exert an important role in improving gastrointestinal functions, and thus date palm fruits can be used as a natural luxative to regulate intestinal transit and promote regular bowel movements [Table/Fig-5] [2,5,11,12,18,23,27,29,37,38,41,42,45-50,52-55].
Date palm fruit components and their common functions and health benefits.
| Date palm fruits components | Common function | Health benefits | References |
|---|
| Carbohydrates |
| Non-starch polysaccharides (NSPs) | 1. Regulate intestinal transitPromote regular bowel movements | • Improving gastrointestinal functions | [2,52] |
| 3. Increase satiety and decrease appetite4. Control energy intake | • Maintaining body weight• Reducing the risk of developing obesity and overweight | [5,37,38] |
| 5. Delay gastric emptying6. Lower the digestion and absorption of carbohydrates | • Protecting of developing the risk of type 2 diabetes• Lowering the glycaemic response• Improving insulin sensitivity | [23,42] |
| Fructose | 1. Inhibit gluconeogenesis | • Lowering the plasma glucose response | [41] |
| Glucose | 1. Provide instant energy | • Health option for breaking fast• Treating hypoglycaemia | [18,47] |
| Minerals |
| Potassium (K) | 1. Regulate blood pressure2. Balance the body’s nervous system and fluids3. Regulate heart rate | • Protecting against strokes and coronary heart diseases | [53,54] |
| Bioactive compounds |
| Phytosterols | 1. Block the absorption of dietary cholesterol into the bloodstream2. Inhibit the re-absorption of cholesterol from bile acids | • Lowering low density lipoprotein (LDL) cholesterol | [27] |
| Phenolics compounds | 1. Inhibit α-glucosidase and α-amylase activity2. Reduce the availability of glucose | • Lowering plasma glucose response | [29] |
| 3. Stimulate uterine myometrial cells4. Increase sensitivity of the uterus5. Reduce postpartum haemorrhage6. Increase the production of milk | • Increasing cervical dilation and uterine contractions• Shortening the labour• Inducing labour naturally• Improving breastfeeding | [45,46] |
| 7. Scavenge free radicals8. Inhibit oxidation reactions9. Absorb and neutralize the free radicals10. Prevent human cells damages11. Inhibit antitumor activity12. Interfere with the mutagenicity | • Improving general human health• Preventing against various oxidative stress-related diseases | [11,12,27,49,55] |
| 13. Activate the host immune system14. Disrupt the bacterial membrane15. Interfere with the bacterial enzymes | • Preventing or treating microbial infections | [48,50] |
Consumption of Date Palm Fruits and Controlling Weight
It is well known that a high NSP diet is highly recommended for maintaining a healthy body weight. As indicated above, DPFs are considered as a good source of NSPs [2]. Insoluble NSPs possess several health benefits, such as promoting weight control by increasing satiety and decreasing appetite [5]. Increased satiety leads to the promotion of energy intake control and a reduced risk of developing obesity and overweight [38]. Recently, it has been found that the association between DPF consumption and weight gain was negligible, indicating that the consumption of DPFs is not responsible for weight gain [37].
The Anti-diabetic Significance of Date Palm Fruits
One of the most important concerns among scientists is whether regular consumption of dates increases the risk of chronic diseases such as diabetes. The majority of scientists and the general public believe that diabetic patients should limit or even avoid consumption of DPFs due to their high content of monosaccharides such as glucose and fructose. However, the consumption of DPFs has not been found to have deleterious effects on serum glucose or to be associated with the prevalence of type 2 diabetes [17,36]. Indeed, DPF components may contribute to diabetes therapy and delay the development of diabetes-related complications [39]. The role of DPF constituents in controlling diabetes is still not fully understood. However, a study on alternative sweeteners showed that granulated date sugar exhibited a potential antidiabetic capacity, suggesting that sugar derived from dates is considered an excellent natural alternative sweetener for diabetic patients [30]. This antidiabetic effect could potentially be attributed to the presence of phenolic compounds that play a role in inhibiting α-glucosidase and α-amylase activity [30]. The inhibition of carbohydrate digestion may result in reducing the plasma glucose response to carbohydrates by reducing the availability of glucose to be absorbed from the small intestine [30].
Moreover, as stated previously, the mean GI value of DPFs falls into a low category [5-9]. The low glycaemic response to DPFs has not only been found in healthy individuals but was also found to be rather lower in type 2 diabetic patients [9]. This could be explained by the presence of a considerable amount of fructose and NSPs in DPFs. In fact, fructose is less diabetogenic than glucose [40]. It has been found that fructose lowers the plasma glucose response by inhibiting gluconeogenesis [41].
Furthermore, soluble and insoluble NSPs in DPFs play an important role in lowering the glycaemic response to DPFs [Table/Fig-5]. NSPs work as a barrier, delaying gastric emptying and reducing the digestion and absorption of carbohydrates [42]. It is evident that high-NSP foods are linked to a favourable effect on insulin sensitivity [43]. Studies have shown a significant association between dietary NSPs and decreased risk of diabetes, supporting the protective role of NSPs in the development of diabetes [23,44].
Moreover, the average GL value of DPFs, as shown in [Table/Fig-2], also falls into the low category. This indicates that both the quality and quantity of DPF carbohydrates exhibit a favourable influence on postprandial glucose response. In fact, GI and GL are potential tools for planning meals and assessing disease risk associated with dietary carbohydrate intake [25]. The importance of GI and GL in preventing type 2 diabetes has been reported in prospective cohort studies [23,44]. Therefore, DPFs may play a role in the management and prevention of type 2 diabetes among Arabian Peninsula inhabitants, where DPFs are frequently consumed on a daily basis.
Consumption of Date Palm Fruits during Late Pregnancy and Postpartum
One of the most interesting health issues related to DPF consumption is that they have been shown to have a contractile property on the uterus during the late trimester of pregnancy [45]. DPF components also possess an oxytocin-like effect that stimulates uterine myometrial cells, increases sensitivity of the uterus, reduces the need for labour induction and augmentation, and induces labour naturally and spontaneously [45,46]. Studies have confirmed that the consumption of six DPFs per day during the final weeks of gestation is associated with an increase in cervical dilation and uterine contractions. It is recommended to include five to seven DPFs in the daily diet during the last weeks of the third trimester of pregnancy to make the delivery process easy and shorten the labour [46].
In addition, the ingestion of DPFs has a beneficial effect on women after delivery, by reducing postpartum haemorrhage and increasing the production of milk for breastfeeding [46].
Date Palm Fruits for Breaking Fast
DPFs are an important component of Middle Eastern diets, particularly for breaking the fast during fasting month worldwide [47]. In fact, DPFs provide instant energy due to their content of glucose and fructose [18]. These readily absorbed sugars make the DPFs the ideal option that is recommended for breaking long-term fasts. Moreover, as DPFs provide natural readily absorbed carbohydrates, this feature makes them the best for treating hypoglycaemia in diabetic patients.
Antioxidant, Anticancer and Antimutagenic Activities of Date Palm Fruits
Date palm trees are adapted to grow in harsh environments, such as arid and semi-arid regions. This adaptation may explain the high antioxidant activity exhibited by DPFs. The antioxidant properties of DPFs exert an effective role in protecting humans from oxidative species [11,12] by acting as free radical scavengers [10,27]. Free radicals are highly reactive components and are involved in activating carcinogenic substances, leading to cellular oxidation reactions, which cause damage to the human cells [10]. The antioxidants in DPFs play a role in inhibiting oxidation reactions and scavenging any free radical intermediates by absorbing and neutralising these radicals [10,12]. This natural action of antioxidants protects the human body from oxidative stress-related diseases, such as neurodegenerative diseases and cancer [27]. Additionally, DPF components exhibit antitumour activities, which have been shown to be associated with the presence of β-glucan [48].
Furthermore, DPF components exert antimutagenic effects by interfering with mutagenicity [1,49]. This kind of activity refers to the presence of bioactive compounds present in DPFs, such as phenolic acids, anthocyanins, β-carotene and selenium [1,49].
Anti-inflammatory and Antimicrobial Activities of Date Palm Fruits
Some Saudi DPF cultivars have been tested for antibacterial properties, and it has been found that different cultivars exhibited different antibacterial activities [50]. The mechanism underlying the antimicrobial activities of DPFs may be attributed to the DPF content of phenolic components, which play an important role in activating the host immune system in addition to their ability to disrupt the bacterial membrane, or interfere with the bacterial enzymes [48]. In addition, DPF components play important roles as anti-inflammatory agents due to their strong ability to act as free radical scavengers [51]. The use of natural products, such as DPF extract, is an effective way to prevent or treat microbial infections [Table/Fig-5].
Conclusion(s)
This review demonstrated the functional properties of DPF contents where they play an important role in securing nutrients and protecting the human body from various chronic degenerative diseases due to their antidiabetic, antimicrobial, antimutagenic, anti-inflammatory, and anticancer activities. Additionally, the low to moderate influences of DPFs on glycaemic and insulinaemic responses, and their high non starch polysaccharide content indicates that patients with diabetes can include five to seven DPFs into their diets on a daily basis. All these nutritional and functional benefits of DPFs suggest that DPF constituents can be a potential ingredient for nutraceutical and therapeutic applications. More research on the functional applications of DPFs is required to increase their use as a healthy food.
[1]. Tang ZX, Shi LE, Aleid SM, Date fruit: chemical composition, nutritional and medicinal values, products J Sci Food Agr 2013 93(10):2351-61.10.1002/jsfa.615423553505 [Google Scholar] [CrossRef] [PubMed]
[2]. Al-Farsi MA, Lee CY, Nutritional and functional properties of dates: a review Crit Rev Food Sci Nutr 2008 48(10):877-87.10.1080/1040839070172426418949591 [Google Scholar] [CrossRef] [PubMed]
[3]. Al-Farsi M, Alasalvar C, Al-Abid M, Al-Shoaily K, Al-Amry M, Al-Rawahy F, Compositional and functional characteristics of dates, syrups and their by-products Food Chem 2007 104(3):943-47.10.1016/j.foodchem.2006.12.051 [Google Scholar] [CrossRef]
[4]. Al-Farsi M, Alasalvar C, Morris A, Baron M, Shahidi F, Compositional and sensory characteristics of three native sun-dried date (Phoenix dactylifera L.) varieties grown in Oman J Agri Food Chem 2005a 53(19):7586-91.10.1021/jf050578y16159190 [Google Scholar] [CrossRef] [PubMed]
[5]. Gourchala F, Mihoub F, Derradj M, Henchiri C, Effect of Algerian varieties dates on glycaemic, arterial blood pressure and satiety responses Asian Journal of Pharmaceutical Research and Health Care 2016 8(2):52-61.10.18311/ajprhc/2016/852 [Google Scholar] [CrossRef]
[6]. Al-Mssallem MQ, Brown JE, Arabic coffee increases the glycaemic index but not insulinemic index of dates Saudi Med J 2013 34(9):923-28.Available from: https://www.ncbi.nlm.nih.gov/pubmed/2404300424043004 [Google Scholar] [PubMed]
[7]. Al-Mssallem MQ, The association between the glycaemic index of some traditional Saudi foods and the prevalence of diabetes in Saudi Arabia: a review article Journal of Diabetes & Metabolism 2014 5(11):45210.4172/2155-6156.1000452 [Google Scholar] [CrossRef]
[8]. AlGeffari MA, Almogbel ES, Alhomaidan HT, El-Mergawi R, Barrimaha IA, Glycaemic indices, glycaemic load and glycaemic response for seventeen varieties of dates grown in Saudi Arabia Ann Saudi Med 2016 36(6):397-403.10.5144/0256-4947.2016.39727920411 [Google Scholar] [CrossRef] [PubMed]
[9]. Alkaabi JM, Al-Dabbagh B, Ahmad S, Saadi HF, Gariballa S, Al Ghazali M, Glycaemic indices of five varieties of dates in healthy and diabetic subjects Nutr J 2011 10:59-68.Available from: http://www.nutritionj.com/content/10/1/5910.1186/1475-2891-10-5921619670 [Google Scholar] [CrossRef] [PubMed]
[10]. Vayalil PK, Bioactive compounds, nutritional and functional properties of date fruit. In: Siddiq M, Aleid SM, KaderAA (eds.) Dates: postharvest science, processing technology and health benefits 2014 Chichester, UKJohn Wiley & Sons Ltd10.1002/9781118292419.ch12 [Google Scholar] [CrossRef]
[11]. Al-Farsi M, Alasalvar C, Morris A, Baron M, Shahidi F, Comparison of antioxidant activity, anthocyanins, carotenoids, and phenolics of three native fresh and sun-dried date (Phoenix dactylifera L.) varieties grown in Oman J Agri Food Chem 2005b 53(19):7592-99.10.1021/jf050579q16159191 [Google Scholar] [CrossRef] [PubMed]
[12]. Al-Turki S, Shahba MA, Stushnoff C, Diversity of antioxidant properties and phenolic content of date palm (Phoenix dactylifera L.) fruits as affected by cultivar and location J Food Agri Environ 2010 8(1):253-60.Available from: https://www.researchgate.net/publication/266506950 [Google Scholar]
[13]. Guo C, Yang J, Wei J, Li Y, Xu J, Jing Y, Antioxidant activities of peel, pulp and seed fractions of common fruits as determined by FRAP assay Nutrition Research 2003 23(12):1719-26.10.1016/j.nutres.2003.08.005 [Google Scholar] [CrossRef]
[14]. Hamad I, Abdelgawad H, Jaouni SK, Zinta G, Asard H, Hassan SH, Metabolic analysis of various date palm fruit (Phoenix dactylifera L.) cultivars from Saudi Arabia to assess their nutritional quality Molecules 2015 20(8):13620-41.10.3390/molecules20081362026225946 [Google Scholar] [CrossRef] [PubMed]
[15]. Liu RH, Potential synergy of phytochemicals in cancer prevention: Mechanism of action J Nutr 2004 134(12)(Suppl):3479S-85S.10.1093/jn/134.12.3479S15570057 [Google Scholar] [CrossRef] [PubMed]
[16]. Vayalil PK, Date fruits (Phoenix dactylifera Linn): an emerging medical food Crit Rev Food Sci Nutr 2012 52(3):249-71.10.1080/10408398.2010.49982422214443 [Google Scholar] [CrossRef] [PubMed]
[17]. Al-Mssallem MQ, Consumption of dates among Saudi adults and its association with the prevalence of type 2 diabetes Asian J Clin Nutr 2018 10(2):58-64.0.3923/ajcn.2018.58.64 [Google Scholar] [CrossRef]
[18]. Ali A, Al-Kindi YS, Al-Said F, Chemical composition and glycaemic index of three varieties of Omani dates Int J Food Sci Nutr 2009 60(S4):51-62.10.1080/0963748080238909418946799 [Google Scholar] [CrossRef] [PubMed]
[19]. Miller CJ, Dunn EV, Hashim IB, The glycaemic index of dates and dates/yoghurt mixed meals. Are dates ‘the candy that grows on trees’? Eur J Clin Nutr 2003 57(3):427-30.10.1038/sj.ejcn.160156512627179 [Google Scholar] [CrossRef] [PubMed]
[20]. Alkaabi J, Al-Dabbagh B, Saadi H, Gariballa S, Yasin J, Effect of traditional Arabic coffee consumption on the glycaemic index of Khalas dates tested in healthy and diabetic subjects Asia Pac J Clin Nutr 2013 22(4):565-73.10.6133/apjcn.2013.22.4.0924231017 [Google Scholar] [CrossRef] [PubMed]
[21]. Ba-Jaber AS, Fares E, Al-Rakban M, Al-Kahtani H, Dafallah A, Glycaemic Index (GI) of some popular Saudi Dates and the effect of their composition on the GI Arabic J Foods Nutr 2006 15:6-13.Available from: http://hdl.handle.net/123456789/9786 [Google Scholar]
[22]. Miller CJ, Dunn EV, Hashim IB, Glycaemic index of 3 varieties of dates Saudi Med J 2002 23(5):536-38. [Google Scholar]
[23]. Salmeron J, Ascherio A, Rimm EB, Colditz GA, Spieqelman D, Jenkins DJ, Dietary fiber, glycaemic load, and risk of NIDDM in men Diabetes Care 1997 20(4):545-50.10.2337/diacare.20.4.545 [Google Scholar] [CrossRef]
[24]. Largua RT, Claudio VS, Nutrition and diet therapy reference dictionary 2004 5th EdnUKBlackwell Publishing Ltd [Google Scholar]
[25]. Livesey G, Taylor R, Livesey HF, Buyken AE, Jenkins DJ, Augustin LS, Dietary glycaemic index and load and the risk of type 2 diabetes: a systematic review and updated meta-analyses of prospective cohort studies Nutrients 2019 11(6):128010.3390/nu1106128031195724 [Google Scholar] [CrossRef] [PubMed]
[26]. Murthy HN, Dandin VS, Zhong JJ, Paek KY, Strategies for enhanced production of plant secondary metabolites from cell and organ cultures. In: Paek KY, Murthy H, Zhong JJ (eds) Production of biomass and bioactive compounds using bioreactor technology 2014 DordrechtSpringer10.1007/978-94-017-9223-3_20 [Google Scholar] [CrossRef]
[27]. El Hadrami A, Daayf F, El Hadrami I, Secondary metabolites of date palm. In: Jain SM, Al-Khayri J, Johnson D (eds) Date palm biotechnology 2011 DordrechtSpringer10.1007/978-94-007-1318-5_31 [Google Scholar] [CrossRef]
[28]. Naik PM, Al-Khayri JM, Cell suspension culture as a means to produce polyphenols from date palm (Phoenix dactylifera L.) Science and Agrotechnology (Ciência e Agrotecnologia) 2018 42(5):464-73.10.1590/1413-70542018425021118 [Google Scholar] [CrossRef]
[29]. Ranilla LG, Kwon Y, Genovese MI, Lajolo FM, Shetty K, Antidiabetes and antihypertension potential of commonly consumed carbohydrate sweeteners using In vitro models J Med Food 2008 11(2):337-48.10.1089/jmf.2007.68918598178 [Google Scholar] [CrossRef] [PubMed]
[30]. Elleuch M, Besbes S, Roiseux O, Blecker C, Derroanne C, Drira N, Date flesh: chemical composition and characteristics of the dietary fibre Food Chem 2008 111(3):676-82.10.1016/j.foodchem.2008.04.036 [Google Scholar] [CrossRef]
[31]. Kaczmarczyk MM, Miller MJ, Freund GG, The health benefits of dietary fiber: beyond the usual suspects of type 2 diabetes mellitus, cardiovascular disease and colon cancer Metabolism: Clinical and Experimental 2012 61(8):1058-66.10.1016/j.metabol.2012.01.01722401879 [Google Scholar] [CrossRef] [PubMed]
[32]. Saura-Calixto F, Dietary fiber as a carrier of dietary antioxidants: an essential physiological function J Agri Food Chem 2011 59(1):43-49.10.1021/jf103659621142013 [Google Scholar] [CrossRef] [PubMed]
[33]. Awad MA, Al-Qurashi AD, Mohamed SA, Antioxidant capacity, antioxidant compounds and antioxidant enzyme activities in five date cultivars during development and ripening Scientia Horticulturae 2011 129(4):688-93.10.1016/j.scienta.2011.05.019 [Google Scholar] [CrossRef]
[34]. Al-Alawi RA, Al-Mashiqri JH, Al-Nadabi JSM, Al-Shihi BI, Baqi Y, Date palm tree (Phoenix dactylifera L.): natural products and therapeutic options Frontiers in Plant Science 2017 8:84510.3389/fpls.2017.0084528588600 [Google Scholar] [CrossRef] [PubMed]
[35]. Al-Mssallem IS, Hu S, Zhang X, Lin Q, Liu W, Tan J, Genome sequence of the date palm Phoenix dactylifera L Nat Commun 2013 4:227410.1038/ncomms327423917264 [Google Scholar] [CrossRef] [PubMed]
[36]. Rock W, Rosenblat M, Borochov-Neori H, Volkova N, Judeinstein S, Elias M, Effects of date (Phoenix dactylifera L., Medjool or Hallawi variety) consumption by healthy subjects on serum glucose and lipid levels and on serum oxidative status: a pilot study J Agri Food Chem 2009 57(17):8010-17.10.1021/jf901559a19681613 [Google Scholar] [CrossRef] [PubMed]
[37]. Al-Mssallem MQ, Elmulthum NA, Elzaki RM, Nutrition security of date palm fruit: an empirical analysis for Al-Ahsa region in Saudi Arabia KFU-Scientific Journal 2019 20(2):47-54. [Google Scholar]
[38]. Kristensen M, Jensen MG, Dietary fibres in the regulation of appetite and food intake. Importance of viscosity Appetite 2011 56(1):65-70.10.1016/j.appet.2010.11.14721115081 [Google Scholar] [CrossRef] [PubMed]
[39]. Malviya N, Jain S, Malviya S, Antidiabetic potential of medicinal plants Acta Poloniae Pharmaceutica 2010 67(2):113-18.https://www.ncbi.nlm.nih.gov/pubmed/2036978720369787 [Google Scholar] [CrossRef]
[40]. Ali SA, Parveen N, Ali AS, Links between the Prophet Muhammad (PBUH) recommended foods and disease management: A review in the light of modern superfoods International Journal of Health Sciences 2018 12(2):61-69.https://www.ncbi.nlm.nih.gov/pubmed/2959969729599697 [Google Scholar] [PubMed]
[41]. Evans RA, Frese M, Romero J, Cunningham JH, Mills KE, Fructose replacement of glucose or sucrose in food or beverages lowers postprandial glucose and insulin without raising triglycerides: a systematic review and meta-analysis Am J Clin Nutr 2017 106(2):506-18.10.3945/ajcn.116.14515128592611 [Google Scholar] [CrossRef] [PubMed]
[42]. Anderson JW, Baird P, Davis Jr RH, Ferreri S, Knudtson M, Koraym A, Health benefits of dietary fiber Nutr Rev 2009 67(4):188-205.10.1111/j.1753-4887.2009.00189.x19335713 [Google Scholar] [PubMed] [PubMed]
[43]. Liese A, Schulz M, Fang F, Wolever T, D’Agostino RJ, Sparks K, Mayer-Davis EJ, Dietary glycaemic index and glycaemic load, carbohydrate and fiber intake, and measures of insulin sensitivity, secretion, and adiposity in the Insulin Resistance Atherosclerosis Study Diabetes Care 2005 28(12):2832-38.10.2337/diacare.28.12.283216306541 [Google Scholar] [CrossRef] [PubMed]
[44]. Sluijs I, van der Schouw YT, van der AD, Spijkerman AM, Grobbee DE, Beulens JW, Carbohydrate quantity and quality and risk of type 2 diabetes in the European Prospective Investigation into Cancer and Nutrition-Netherlands (EPIC-NL) study Am J Clin Nutr 2010 92(4):905-11.10.3945/ajcn.2010.2962020685945 [Google Scholar] [CrossRef] [PubMed]
[45]. Al-Kuran O, Al-Mehaisen L, Bawadi H, Beitawi S, Amarin Z, The effect of late pregnancy consumption of date fruit on labour and delivery J Obstet Gynaecol 2011 31(1):29-31.10.3109/01443615.2010.52226721280989 [Google Scholar] [CrossRef] [PubMed]
[46]. Nasiri M, Gheibi Z, Miri A, Rahmani J, Asadi M, Sadeghi O, Effects of consuming date fruits (Phoenix dactylifera Linn) on gestation, labor, and delivery: An updated systematic review and meta-analysis of clinical trials Complementary Therapies in Medicine 2019 45:71-84.10.1016/j.ctim.2019.05.01731331586 [Google Scholar] [CrossRef] [PubMed]
[47]. Al-Shahib W, Marshall RJ, The fruit of the date palm: its possible use as the best food for the future? Int J Food Sci Nutr 2003 54(4):247-59.10.1080/0963748012009198212850886 [Google Scholar] [CrossRef] [PubMed]
[48]. Iranshahi M, Rezaee R, Parhiz H, Roohbakhsh A, Soltani F, Protective effects of flavonoids against microbes and toxins: the cases of hesperidin and hesperetin Life Sci 2015 137:125-32.10.1016/j.lfs.2015.07.01426188593 [Google Scholar] [PubMed] [PubMed]
[49]. Vayalil PK, Antioxidants and antimutagenic properties of aqueous extract of date fruit (Phoenix dactylifera L. Arecaceae) J Agri Food Chem 2002 50(3):610-17.10.1021/jf010716t11804538 [Google Scholar] [CrossRef] [PubMed]
[50]. Samad MA, Hashim SH, Simarani K, Yaacob JS, Antibacterial properties and effects of fruit chilling and extract storage on antioxidant activity, total phenolic and anthocyanin content of four date palm (Phoenix dactylifera) cultivars Molecules 2016 21(4):41910.3390/molecules2104041927023514 [Google Scholar] [CrossRef] [PubMed]
[51]. Bouhlali ET, El Hilaly J, Ennassir J, Benlyas M, Alem C, Amarouch M, Filali-Zegzouti Y, Anti-inflammatory properties and phenolic profile of six Moroccan date fruit (Phoenix dactylifera L.) varieties Journal of King Saud University- Science 2018 30(4):519-26.10.1016/j.jksus.2017.08.011 [Google Scholar] [CrossRef]
[52]. Manickavasagan A, Mohamed Essa M, Sukumar E, Dates: production, processing, food, and medicinal values 2012 Boca Raton, FL, USACRC Press Taylor and Francis Group10.1201/b1187422492604 [Google Scholar] [CrossRef] [PubMed]
[53]. Haddy FJ, Vanhoutte PM, Feletou M, Role of potassium in regulating blood flow and blood pressure Am J Physiol Regul Integr Comp Physiol 2006 290(3):R546-52.10.1152/ajpregu.00491.200516467502 [Google Scholar] [CrossRef] [PubMed]
[54]. Pamnani MB, Bryant HJ, Clough DL, Schooley JF, Increased dietary potassium and magnesium attenuate experimental volume dependent hypertension possibly through endogenous sodium-potassium pump inhibitor Clin Exp Hypertens 2003 25(2):103-15.10.1081/CEH-12001793112611422 [Google Scholar] [CrossRef] [PubMed]
[55]. Ishurd O, Kennedy JF, The anti-cancer activity of polysaccharide prepared from Libyan dates (Phoenix dactylifera L.) Carbohydrate Polymers 2005 59(4):531-35.10.1016/j.carbpol.2004.11.004 [Google Scholar] [CrossRef]