ACCORDING to key findings from National Health and Morbidity Survey (NHMS) 2024, only 13% adolescents and 17% adults consumed 2 servings of fruits daily, while just 5% of adolescents and 12% adults consumed 3 servings of vegetables per day. The data showed that inadequate fruits and vegetables consumption contributed to insufficient Vitamin A intake in 55% adolescents and 63% of adults. With regard to Vitamin C, about 78% of adolescents and 74% of adults consumed insufficient Vitamin C.
Fruits and vegetables are well-established sources of dietary fiber, essential vitamins, and minerals. Numerous epidemiological and clinical studies have demonstrated that high consumption of fruits and vegetables is associated with a reduced risk and lower mortality rates from various chronic diseases, including cancer, type 2 diabetes mellitus, and cardiovascular disease. This protective effect is primarily attributed to the presence of vitamins such as vitamin C, vitamin E, and ß-carotene.
Hydrophilic antioxidants, particularly vitamin C, constitute approximately 85% of the total antioxidant content in fruits and vegetables. These vitamins play key roles in maintaining physiological homeostasis and protecting cellular components from oxidative damage. Vitamin C enhances the body’s antioxidant defense mechanisms. Beta-carotene, abundant in brightly pigmented fruits and vegetables, has been shown to mitigate oxidation of low-density lipoprotein (LDL) cholesterol and support immune function by modulating the activity of antioxidant enzymes.
According to the Management and Science University (MSU) Senior Lecturer at Faculty of Health and Life Sciences, Dr. Tan Bee Ling, “In addition to vitamins, fruits and vegetables are rich in bioactive compounds such as flavonoids, which exhibit a broad spectrum of biological activities including antioxidant, antimicrobial, anti-inflammatory, and antitumor effects. Among these, anthocyanins represent one of the most prevalent classes of flavonoids in plant-based foods. These compounds are not only responsible for the characteristic red, blue, and purple pigmentation but also contribute significantly to the overall antioxidant capacity of the diet.
Vitamin A
Vitamin A is a fat-soluble vitamin essential for maintaining numerous physiological functions, including vision, immune function, and cell growth and differentiation. In the visual cycle, vitamin A is a precursor to retinal, a component of rhodopsin, which is necessary for low-light and color vision. It also plays a crucial role in maintaining the integrity of epithelial tissues and mucosal barriers, thereby supporting immune defense mechanisms. In addition, vitamin A regulates gene expression through its active metabolite, retinoic acid, which influences cellular growth and differentiation. Dietary vitamin A exists in two primary forms, namely preformed vitamin A (retinol and its esters), found predominantly in animal-derived foods such as liver, dairy products, and eggs; and provitamin A carotenoids, notably ß-carotene, found in orange, yellow, and dark green leafy vegetables and fruits. The latter are converted enzymatically to retinol in the human body, although conversion efficiency can be influenced by individual nutritional status, genetics, and overall dietary composition.
Carotenoids are a diverse class of naturally occurring pigments synthesized by plants, algae, and photosynthetic bacteria, and they play multiple roles in both plant physiology and human health. Among these, lycopene is particularly notable for its potent photoprotective properties and its ability to quench singlet oxygen species, thereby mitigating oxidative damage. In non-photosynthetic plant tissues, carotenoids serve as precursors to phytohormones, act as visual attractants for pollinators through pigmentation, and antioxidants.
During fruit and seed ripening, carotenoid biosynthesis is often upregulated, leading to marked color transitions such as shift from green to red or purple hues. This change is largely attributed to the accumulation of anthocyanins and/or carotenoids. For instance, in tomatoes, the pericarp transitions from greenish-yellow to deep red during ripening due to the conversion of colorless phytoene into lycopene.
Carotenes represent some of the earliest intermediates in the carotenoid biosynthetic pathway and are ubiquitous across photosynthetic organisms. In the human diet, carotenoids such as ß-carotene, a-carotene, ß-cryptoxanthin, lycopene, lutein, and zeaxanthin are of particular significance. These six compounds account for over 90% of total carotenoids detected in human tissues and are associated with various protective health effects. Several carotenoids including ß-carotene, a-carotene, and ß-cryptoxanthin, exhibit provitamin A activity and can be enzymatically converted into retinol, an essential nutrient for vision, immune function, and epithelial integrity.
Lutein and zeaxanthin, in particular, are highly concentrated in the macula of the human retina, where they filter high-energy blue light and counteract oxidative stress, thereby contributing to the prevention of age-related macular degeneration and cataract formation. Age-related macular degeneration remains one of the leading causes of irreversible blindness among individuals over the age of 65. The antioxidant capacity of these carotenoids underpins their protective role in ocular health, emphasizing the importance of adequate dietary intake of carotenoid-rich fruits and vegetables.
Vitamin C
Ascorbic acid, commonly referred to vitamin C, is a water-soluble essential micronutrient that plays a crucial role in various physiological processes. It is obtained primarily through the diet, with significant amounts found in a variety of plant-based foods, including cruciferous vegetables such as broccoli, tomatoes, and citrus fruits like oranges and lemons.
Vitamin C functions as a potent antioxidant, capable of donating electrons to neutralize reactive oxygen species and other free radicals, thereby reducing oxidative stress within cells. Upon electron donation, vitamin C is converted into a relatively stable intermediate known as the ascorbyl radical, which can be recycled back to its active form. This redox activity contributes significantly to cellular defense mechanisms against oxidative damage.
Beyond its antioxidant role, vitamin C is involved in several biosynthetic pathways, including collagen synthesis, neurotransmitter production, and immune system regulation. Accumulating evidence indicates that oxidative stress, driven by excessive reactive oxygen species accumulation, may induce the formation of mutagenic compounds and activate pro-inflammatory and oncogenic pathways. In this context, regular intake of antioxidant-rich foods, including those high in vitamin C, has been associated with a reduced risk of chronic diseases, such as cardiovascular disorders, certain cancers, and age-related degenerative conditions.
Given its multifaceted biological functions and antioxidant properties, vitamin C contributes to the maintenance of cellular homeostasis, supports mitochondrial energy metabolism, and plays a protective role in immune defense. Therefore, increasing the consumption of vitamin C rich food may represent an effective dietary strategy for mitigating oxidative damage and promoting long-term health. Consuming 2 servings of fruits and 3 servings of vegetables daily is recommended to help ensure adequate intake of vitamins A and C. Collectively, the synergistic effects of vitamins and phytochemicals in fruits and vegetables highlight their essential contribution to the prevention of chronic diseases and the promotion of overall health.
