Fruits and vegetables are part of ideal diet as they supply many plant compounds that provide protection against the emergence of disease, as well as balancing the nutritional requirements of the body

logoFruits and Vegetables: Health Aspects

Fruits and vegetables have long been included as part of the healthy diet as they contain vitamins, especially vitamin A and C, mineral, antioxidants, and dietary fiber. According to United States of Department of Agriculture, as stated by Joanne L. Slavin and Beate Lloyd in their review paper (Health Benefits of Fruits and Vegetables, published in the journal Advances in Nutrition, 3: 506–516, 2012), fruits and vegetables are categorised into different groups such as dark green vegetables, red or orange vegetables, beand and peas, starchy vegetables, and other vegetables, while fruits are categorised as all fresh, canned, frozen, dried fruits, and fruit juices. These categorisation is important as a guideline for policy and diet programme.

As oulined in the Food Sources page, vegetables and fruits contain vitamins (especially A and C), minerals, folate and other phytochemicals that have significant contribution to health. However, the effect of plant foods to health can be categorised into two different aspects, protective and adverse effects. Plant foods give protective effect on health as they contain components that give protection to the body from diseases. On the other hand, some plant food components may also give adverse effects to the body if consumed and leave residus which triggers physiological disorder. Some of the plant foods components that give protective and adverse effects on health is summarised in Table 1.

Table 1. Protective and Adverse Effects Components of Fruits and Vegetables

 

Protective components

 

Adverse

Dietary fiber
Vitamin C
Vitamin E
Carotenoids
Flavonoids
Folic acid
Selenium
Dithiolthiones
Glucosinolates
Indoles
Isothiocyanates
Coumarins
Phenol
Protease inhibitors
Plant sterols
Isoflavones/lignans
Saponins
Inositol hexaphosphate
Allium compounds
Limonene

Aflatoxin
Pesticides
Herbicides
Nitrates
Alar
Goitrogens
Enzyme inhibitors
Phenolic compounds
Saponins
Inositol hexaphosphate

 

Source: Joanne L. Slavin and Beate Lloyd. 2012. Health benefits of fruits and vegetables. Adv. Nutr. 3:506-512.

Health Benefits of Fruits

Grape

grapes

Several studies have suggested that consumption of fruits give health benefit. Grape, for example, has been extensively studied to establish its role in promoting health, such as reducing the risk of Cardio Vascular Disease (CVD). Red wine consumption has been suggested as providing protection effect to CVD due to its high content of antioxidants, especially flavonoids, as suggested by Vislocky and Fernandez (2010) in their study (Biomedical effects of grape products, Nutr Rev 68:656-670). Another study conducted by Dohadwala and Vita (2009), (Grapes and cardiovascular disease, Journal of Nutrition, 139:S1788-1793) , also suggested that that grape polyphenol can reduce atherosclerosis by inhibiting LDL oxidation and platelet aggregation, improving endothelial function, lowering blood pressure, reducing inflammation, and prevent cell senescence by the synthesis of a novel protein. Grapes are also an excellent source of important mineral, such as manganese, potassium, as well as vitamins C, vitamin B6, and thiamin. One of important phytochemical found in grape is resveratrol, a polyphenol antioxidant which is believed lowers risk of cardiovascular disease, and reduces oxidation.

Resveratrol (trans-3,5, 40-trihydroxy stilbene) is a polyphenol phytoalexin present in grape and red wine, cranberry, mulberry,
lingberry, bilberry, jackfruit, peanut gnetum, and the butterfly
orchid tree and posseses diverse biochemical and physiological properties, such as estrogenic, anti platelet, anti inflammatory, as well as chemoprevention and cardioprotection.

A review conducted by Dipak K. Das, Subhendu Mukherjee, and Diptarka Ray published in journal Heart Fail Rev (Erratum to: Resveratrol and red wine, healthy heart and longevity, Heart Fail Rev, 2011, 16:425–435), suggested that resveratrol can induce the expression of several longevity genes including Sirt1, Sirt3, Sirt4, FoxO1, Foxo3a and PBEF and prevent aging-related decline in cardiovascular function including cholesterol level and inflammatory response. However, several studies suggested that it is unable to affect actual survival or life span of mice. Resveratrol also posses potential anticancer activity in various cancer cells at the initiation, promotion and progession stages.

Grape (green, raw) contains micronutrients: vitamin A (<4 µg/100g), thiamin (0.04 µg/100g), riboflavin (0.01 µg/100g), niacin (0.2 mg/100g), vitamin C (2 mg/100g), vitamin E (0.18 mg/100g), vitamin B-6 (0.04 mg/100g), folate (6 µg/100g), panthothenic acid (0.14 mg/100g), biotin (0.2 µg/100g), sodium (1 mg/100g), potassium (217 mg/100g), calcium (8.4 mg/100g), magnesium (6.3 mg/100g), phosphorus (19 mg/100g), iron (0.21 mg/100g), copper (0.07 mg/100g), zinc (<0.06 mg/100g), chloride (44 mg/100g), iodine (1 µg/100g), manganese (0.06 mg/100g), selenium (<0.5 µg/100g).

Red grape (raw) contains: vitamin A (2 µg/100g), thiamin (0.09 µg/100g), riboflavin (0.01 µg/100g), niacin (0.2 mg/100g), vitamin C (3 mg/100g), vitamin E (0.20 mg/100g), vitamin B-6 (0.04 mg/100g), folate (6 µg/100g), panthothenic acid (0.12 mg/100g), biotin (0.2 µg/100g), sodium (1 mg/100g), potassium (213 mg/100g), calcium (811 mg/100g), magnesium (7 mg/100g), phosphorus (18 mg/100g), iron (0.24 mg/100g), copper (0.10 mg/100g), zinc (<0.06 mg/100g), chloride (63 mg/100g), iodine (N/A), manganese (0.06 mg/100g), selenium (<0.5 µg/100g). [Source: Food Composition and Diet Team Public Health Directorate, 2013, Nutrient Analysis of Fruit and Vegetables, United Kingdom, © Crown].

Apple

applesApple is a very popular frit in Europe, American continent, China, and now even almost every country serves apple in many places and occasion. Apple contains many phytochemicals, such as quercetin, catechin, phloridzin, and chlorogenic acid. Those phytochemicals are known as strong antioxidants. Studies suggested that consumption of apples linked to reduced risk of cancer, cardiovascular disease, asthma and diabetes. Apple (raw, flesh and skin) also contains many important micronutrients: vitamin A (2 µg/100g), thiamin (0.04 µg/100g), riboflavin (0.04 µg/100g), niacin (0.1 mg/100g), vitamin C (6 mg/100g), vitamin E (0.09 mg/100g), vitamin B-6 (0.07 mg/100g), folate (<5 µg/100g), panthothenic acid (0.10 mg/100g), biotin (1.1 µg/100g), sodium (1 mg/100g), potassium (100 mg/100g), calcium (5 mg/100g), magnesium (4 mg/100g), phosphorus (8 mg/100g), iron (0.09 mg/100g), copper (0.03 mg/100g), zinc (<0.06 mg/100g), chloride (44 mg/100g), iodine (4 µg/100g), manganese (0.04 mg/100g), selenium (<0.5 µg/100g). [Source: Food Composition and Diet Team Public Health Directorate, 2013, Nutrient Analysis of Fruit and Vegetables, United Kingdom, © Crown].

According to Jeanelle Boyer and Rui Hai Liu in their review, (Apple phytochemicals and their health benefits, Nutrition Journal, 2004, 3:5), apples are a very signficant source of flavonoid that showed the strongest associations with decreased mortality as found in the population of Finnish people. Apple also has the second highest antioxidant activity, after cranberry. A diet with high antioxidant help prevent oxidative stress and may therefore help prevent the chronic disease and slow aging. Some studies have also suggested that consumption of apple linked to the reduced risk of cancer, especially lung cancer and epithelial cancer. Similarly, reduced risk of cardiovascular disease, asthma and bronchial hypersensitivity, were also found associated with the consumption of apple. It is also interesting to note that apple consumption also relates to the decrease of diabetes type II risk. Another important finding is that apple peels contain more antioxidant activity and higher bioactivity than apple flesh. Apples with the peels are also better to inhibit cancer cell proliferation when compared to apples without the peels, suggesting that eating apple with its peels is better than only the flesh.

Oranges

Orange

Oranges contain micronutrients: vitamin A (9 µg/100g), thiamin (0.22 µg/100g), riboflavin (0.03 µg/100g), niacin (0.5 mg/100g), vitamin C (52 mg/100g), vitamin E (0.35 mg/100g), vitamin B-6 (0.05 mg/100g), folate (33 µg/100g), panthothenic acid (0.27 mg/100g), biotin (1.0 µg/100g), sodium (1 mg/100g), potassium (122 mg/100g), calcium (24 mg/100g), magnesium (8 mg/100g), phosphorus (16 mg/100g), iron (0.11 mg/100g), copper (0.03 mg/100g), zinc (<0.06 mg/100g), chloride (73 mg/100g), iodine (1 µg/100g), manganese (0.02 mg/100g), selenium (<0.5 µg/100g). [Source: Food Composition and Diet Team Public Health Directorate, 2013, Nutrient Analysis of Fruit and Vegetables, United Kingdom, © Crown].

Orange also contains flavonoids called hesperidin and naringin and shows cholesterol-lowering potential in human. Orange juice is known to reduce markers related to insulin resistance and cardiovacscular disease, decrease inflammation markers in blood and liver. Christine Morand et al. (Hesperidin contributes to the vascular protective effects of orange juice: a randomized crossover study in healthy volunteers, 2011, Am J Clin Nutr 93:73–80) stated that citrus fruit consumption has been associated with a lower risk of acute coronary events and stroke, reduces oxidative DNA damage, reduces diastolic blood pressure (DBP). The reduced DBP was found associated with the hesperidin, a flavonoid found in orange.

Banana

banana

In addition to its macronutrient contents (read Food Sources page), banan also contains several important micronutrients: vitamin A (4 µg/100g), thiamin (0.15 µg/100g), riboflavin (0.04 µg/100g), niacin (0.7 mg/100g), vitamin C (9 mg/100g), vitamin E (0.16 mg/100g), vitamin B-6 (0.31 mg/100g), folate (14 µg/100g), panthothenic acid (0.35 mg/100g), biotin (2.5 µg/100g), sodium (<5 mg/100g), potassium (330 mg/100g), calcium (6 mg/100g), magnesium (27 mg/100g), phosphorus (23 mg/100g), iron (0.27 mg/100g), copper (0.10 mg/100g), zinc (0.18 mg/100g), chloride (109 mg/100g), iodine (3 µg/100g), manganese (0.36 mg/100g), selenium (<0.5 µg/100g).[Source: Food Composition and Diet Team Public Health Directorate, 2013, Nutrient Analysis of Fruit and Vegetables, United Kingdom, © Crown].

Banana is a significant part of diet in the tropical country. Certain country, such as Uganda, use banana, the East African Highland banana, as a staple food as the primary starch source. Banana is a high calorie fruit, providing siginificant amount of energy. Two bananas give enough energy for one and half hour of workout or walk. The high content of potassium will give a health benefit as it helps in reducing blood pressure, reduces the risk of stroke in older women. It is known that increased intake of potassium reduces blood pressure in people with hypertension, as stated by Nancy J Aburto, Sara Hanson, Hialy Gutierrez, Lee Hooper, Paul Elliott, Francesco P
Cappuccio Cephalon in their publication (Effect of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses, 2013, BMJ, 346: f1378). Banana also contains antioxidant, dopamine and catechins, which reduce the risk of heart disease and degenerative diseases. However, dopamine in banana does not alter hormones or mood. Banana has the highest content of phenolic compounds compared to orange, apple, red grape, peach, lemon, grapefruit, pineapple, pear, cranberry, and strawberry. The phenolic compounds have been linked to high antioxidant activity.

 

Health Benefits of Vegetables

Tomato

tomato

Tomatoes are widely consumed and become major nourishment in the world. It becomes part of many daily menus, as a part of many cookings, tomato juice, or tomato ketchup. Tomato is a nutritionally important vegetable as it synthesises bioactive carotenoid pigments lycopene and β-carotene and the glycoalkaloids dehydrotomatine, α-tomatine, and esculeoside A. It has been reported that lycopene and α-tomatine elicit anticarcinogenic and other beneficial effects in vitro and in vivo, as stated by Mendel Friedman in his review (Anticarcinogenic, Cardioprotective, and Other Health Benefits of Tomato Compounds Lycopene, α‑Tomatine, and Tomatidine in Pure Form and in Fresh and Processed Tomatoes, 2013, Journal of Agricultural and Food Chemistry, 61: 9534−9550).

Lycopene is known to have a strong antioxidant activity and acts as free radical scavengers. Many studies suggested that lycopene and alpha-tomatine may contribute to prevention and therapy of human cancers and cardiovascular diseases.

Tomato (raw) contains micronutrients as follows: vitamin A (58 µg/100g), thiamin (0.04 µg/100g), riboflavin (0.01 µg/100g), niacin (0.6 mg/100g), vitamin C (22 mg/100g), vitamin E (0.52 mg/100g), vitamin B-6 (0.06 mg/100g), folate (23 µg/100g), panthothenic acid (0.29 mg/100g), biotin (1.4 µg/100g), sodium (2 mg/100g), potassium (223 mg/100g), calcium (8 mg/100g), magnesium (8 mg/100g), phosphorus (22 mg/100g), iron (0.24 mg/100g), copper (0.03 mg/100g), zinc (0.10 mg/100g), chloride (84 mg/100g), iodine (2 µg/100g), manganese (0.12 mg/100g), selenium (<0.5 µg/100g). [Source: Food Composition and Diet Team Public Health Directorate, 2013, Nutrient Analysis of Fruit and Vegetables, United Kingdom, © Crown].

In addition to its antioxidant activity, tomato is also a rich source of vitamin A which is a very important nutrient for many physiological activities, such as good vision, bone growth, reproduction, supports immune system, and skin health.

Carrot

carrot

Carrot is a root vegetable that widely available almost everywhere. It is a very popular vegetable, which once was used as a vegetable, but then it is also consumed in the form of juice. Carrot has a high pro-vitamin A content. It also has carotenoid and athocyanin as the major antioxidant components. Carotenoid is the phytochemical component that gives yellow, orange, or red colour to the flesh. Yellow carrot contains lutein which plays a significant role in preventing macular degeneration. Eating carrots may restore vision due to its content of pro-vitamin A. Red carrot contains lycopene, while anthocyanin-rich carrot has a purple colour.

Carrots (raw) contains micronutrients:vitamin A (1961 µg/100g), thiamin (0.13 µg/100g), riboflavin (0.01 µg/100g), niacin (0.2 mg/100g), vitamin C (2 mg/100g), vitamin E (0.09 mg/100g), vitamin B-6 (0.06 mg/100g), folate (8 µg/100g), panthothenic acid (0.27 mg/100g), biotin (0.3 µg/100g), sodium (27 mg/100g), potassium (127 mg/100g), calcium (26 mg/100g), magnesium (7 mg/100g), phosphorus (16 mg/100g), iron (0.23 mg/100g), copper (0.03 mg/100g), zinc (0.11 mg/100g), chloride (122 mg/100g), iodine (<0.7 µg/100g), manganese (0.07 mg/100g), selenium (<0.5 µg/100g). [Source: Food Composition and Diet Team Public Health Directorate, 2013, Nutrient Analysis of Fruit and Vegetables, United Kingdom, © Crown].

Carrot is also a good source of dietary fiber and contains molybdenum which is rarely found in many vegetables. According to João Carlos da Silva Dias in his paper (Nutritional and Health Benefits of Carrots and Their Seed Extracts, published in Food and Nutrition Sciences, 2014, 5:2147-2156), molydenum is an important trace mineral aids in fats and carbohydrate metabolism as well as absorption of iron. Carotenoid presents in carrot is a potent antioxidant which netralises the effect of free radicals and is reported to have anti-carcinogenic effect myeloid and lymphoid leukemia cell lines. It was also reported by Purup, S., Larsen, E. and Christesen in their paper (Differential Effects of Falcarinol and Related Aliphatic C17-Polyacetylenes on Intestinal Cell Proliferation, published in Journal of Agricultural and Food Chemistry, 57:8290-8296) that extracts of carrot had a significant inhibitory effect on cancer cell proliferation. Several experimental evidences have suggested that carrot compounds exert antioxidative, anticarcinogenic, and immunoenhancer effects, as well as anti-diabetic, cholesterol and cardiovascular disease lowering. It is also important to note that anti-hypertensive, hepatoprotective, renoprotective, and wound healing benefits of carrot have also been reported.

Broccoli

broccoli

Broccoli is one of the world's most important and well known vegetable. It is an excellent source of vitamin C (79 mg/100g) and vitamin A (97 µg/100g). Broccoli is low in calorie, fat, cholesterol-free. Broccoli contains a phytochemical, sulforaphane, which has been demonstrated reduced the risk of cancer, as stated by Center for Nutrition, Diet and Health, University of the District of Columbia. Broccoli is also known to have gastroprotective, antimicrobial, antioxidant, anticancer, hepatoprotective, cardioprotective, anti-obesity, anti-diabetic, anti-inflammatory and immunomodulatory activities. There are three broccoli varieties: Calabrese broccoli (the most common variety found in the United States), broccoli rabe (grown in Mediterranean region), and broccolini or baby broccoli (a cross between Chinese kale and calabrese broccoli).

Broccoli (calabrese, raw) contains micronutrients: vitamin A (97 µg/100g), thiamin (0.15 µg/100g), riboflavin (0.12 µg/100g), niacin (0.8 mg/100g), vitamin C (79 mg/100g), vitamin E (1.72 mg/100g), vitamin B-6 (0.13 mg/100g), folate (95 µg/100g), panthothenic acid (0.61 mg/100g), biotin (4.1 µg/100g), sodium (9 mg/100g), potassium (397 mg/100g), calcium (48 mg/100g), magnesium (22 mg/100g), phosphorus (81 mg/100g), iron (1.06 mg/100g), copper (0.08 mg/100g), zinc (0.70 mg/100g), chloride (73 mg/100g), iodine (2 µg/100g), manganese (0.28 mg/100g), selenium (1 µg/100g). [Source: Food Composition and Diet Team Public Health Directorate, 2013, Nutrient Analysis of Fruit and Vegetables, United Kingdom, © Crown].

A study conducted by Young Woon Chang, Jae Young Jang, Yong Ho Kim, Jung-Wook Kim, and Jae-Jun Shim (The Effects of Broccoli Sprout Extract Containing Sulforaphane on Lipid Peroxidation and Helicobacter pylori Infection in the Gastric Mucosa, published in Gut and Liver, Vol. 9, No. 4, July 2015, pp. 486-493) demonstrated that Broccoli Sprout Extract containg Sulforaphane, prevented lipid peroxidation in the gastric mucosa and may play a cytoprotective role in H. pylori-induced gastritis. It is known Helicobacter pylori is responsible for the emergence of gastritis, peptic ulcer disease, and gastric cancer. Studies have shown that people who eat a diet rich in broccoli have a lower risk of some cancers, as stated by A. I. Owis in the review paper (Broccoli; The Green Beauty: A Review, J. Pharm. Sci. & Res. Vol. 7(9), 2015, 696-703).

Beans

beans

Beans, together with peas and lentils, are collectively grouped as legumes or pulses. Beans have become a food of choice of many people as it contains a very low fat, no cholesterol, high protein content more than what is found in general grains. Beans have become staple food in Americas, Middle East, China, and India. In United States dry beans are used interchangebly with legumes, but in Canada and other part of the world it is called pulses. Beans are really fruit but it is often grouped as part of vegetables.

Beans contain micronutrients: vitamin A (47 µg/100g), thiamin (0.12 µg/100g), riboflavin (0.09 µg/100g), niacin (0.8 mg/100g), vitamin C (8 mg/100g), vitamin E (0.44 mg/100g), vitamin B-6 (0.06 mg/100g), folate (58 µg/100g), panthothenic acid (0.11 mg/100g), biotin (1.0 µg/100g), sodium (<0.5 mg/100g), potassium (286 mg/100g), calcium (52 mg/100g), magnesium (25 mg/100g), phosphorus (38 mg/100g), iron (1.04 mg/100g), copper (0.06 mg/100g), zinc (0.38 mg/100g), chloride (69 mg/100g), iodine (2 µg/100g), manganese (0.31 mg/100g), selenium (1 µg/100g). [Source: Food Composition and Diet Team Public Health Directorate, 2013, Nutrient Analysis of Fruit and Vegetables, United Kingdom, © Crown].

According to Donna Winham, Densie Webb, RD, and Amy Barr in their review (Beans and Good Health, published in Nutrition Today, Volume 43  Number 5  September/October, 2008), beans have a nutritional profile that suits for all ages providing cholesterol-free protein, fiber, magnesium, potassium, B vitamins, resistant starch, and the more recently discovered phytonutrients. It is also stated that compared with other sources of carbohydrates, beans exhibit a low glycemic index (GI) and produce a relatively flat blood-glucose response. The soluble fiber in beans, peas, and lentils is highly fermentable in the colon, which is thought to be health enhancing. Laksmi Mahan, Lauren Foster, and Wendy J. Dahl also stated in the their paper (Beans, Peas, and Lentils: Health Benefits, Food Science and Human Nutrition Department, UF/IFAS Extension) that beans also contains 7 g of dietary fiber in a 1/2-cup serving and are especially high in insoluble fiber (USDA 2015). The insoluble fiber is another important health benefit of beans as it bulks stool and decreases transit time through the colon, thereby preventing constipation.

Healthy eating

A healthy eating style is dependent on several factors. The balanced macronutrients, carbohydrate, protein, and fat (lipid), are of paramount importance in achieveing good nutrients level. However, many important food components are found in certain fruits and vegetables, such as grape, apple, thus consumption of fruits and vegetables are also of signficant contributing factors to achieve a healthy eating style.