A comprehensive literature search was performed using the following databases: PubMed, PubMed Central, and the Directory of Open Access Journals (DOAJ). The search covered the time frame from 2018 to 2025, focusing on the most recent and relevant scientific studies. The search was restricted to articles published in English. Commonly used keywords included: “vitamin supplementation,” “B vitamins,” “folate,” “vitamin D,” “vitamin E,” “vitamin A,” “vitamin K,” “vitamin C,” “chronic disease prevention,” “cardiovascular disease,” “cancer,” “cognitive decline,” and “neurodegeneration.”

The initial search yielded a total of 40 articles. After applying the above inclusion and exclusion criteria and conducting relevance screening, 21 articles were selected for detailed review. Data extraction was performed independently by the authors and included:

These studies were then synthesized to assess the preventive potential of specific vitamins on chronic diseases, especially focusing on B vitamins (B6, B12, folate), Vitamin D, Vitamin E, Vitamin A, Vitamin K, Vitamin C, and carotenoids.

Vitamins are vital micronutrients that play a vital role in numerous biochemical and physiological processes, with B vitamins--Folate, B6, and B12 being particularly studied for their roles in neurological health, cardiovascular health, cell metabolic functions, and homocysteine conversion to methionine maintaining optimal homocysteine levels in blood and cognitive decline/neurodegenerative disorders being linked with elevated homocysteine levels 9; further highlighting their essentiality as health maintenance ingredients.

The present review highlights their crucial function as homocysteine conversion helps maintain optimal homocysteine levels which help to maintain optimal homocysteine levels associated with cardiovascular diseases / vascular / cognitive decline / neurodegenerative disorders / risk, which emphasizes their essentiality as health maintenance agents. 8, 9

Studies have consistently linked deficiencies of folate, B6, and B12 with higher homocysteine concentrations that contribute to increased oxidative stress, leading to potential vascular damage as well as age-related cognitive impairments and stroke risk.8 A meta-analysis in this review shows the effectiveness of folate supplementation for lowering homocysteine levels, thereby potentially decreasing stroke risks as well as age-related cognitive decline - consistent with research that shows regular intake of B vitamins may protect from dementia, Alzheimer's disease, and other neurodegenerative conditions. 10

Folate's role in DNA synthesis and repair further underlines its significance as a cancer preventive supplement. However, the inconclusive results on breast cancer risk highlight the urgent need for more nuanced research on how vitamin intake impacts cancer risk across different populations and genetic backgrounds. 32

B vitamins, particularly folate, offer immense public health value in preventing neural tube defects (NTDs). According to systematic reviews and policy evaluations, mandatory folate fortification has significantly decreased NTD incidence rates in many countries. Adequate red blood cell folate levels are reliable biomarkers of maternal folate status, confirming its necessity as preconception folate supplementation among women of reproductive age. 14

This study reviewed B vitamins and fat-soluble ones like vitamins A, D, E, and K as essential to maintaining good health. Fat-soluble vitamins differ from water-soluble ones by being stored within body fat or liver bile; their functions range from immunity, bone health protection, antioxidant defense, blood coagulation, and more. 33

Vitamin D has long been recognized for its key role in calcium metabolism and bone mineralization. However, emerging evidence also links vitamin D deficiency with cardiovascular risks, insulin resistance, autoimmune conditions, and more. Thus, optimal serum 25(OH) D concentrations must be maintained to support immune functions and minimize inflammation - particularly among aging populations. 34

Vitamin E, an extremely potent antioxidant, plays an integral part in protecting cell membranes from oxidative damage and may play an integral part in lowering coronary heart disease (CHD) risk by decreasing LDL oxidative modification.35 Although observational studies and randomized trials indicate cardiovascular benefits from supplementing with Vitamin E, supplementation might prove more advantageous among populations already deficient or with increased levels of oxidative stress stressors. 36

Vitamin A is essential for vision, immune defense, epithelial integrity, reproduction, and embryonic development. It also plays an essential role in embryonic growth. 37 The potential toxicity of excess intake underscores the importance of maintaining an appropriate daily dosage, making responsible and cautious supplementation vital.

Vitamin K plays an essential part in blood clotting and bone metabolism. Recent research suggests that it may be used to prevent arterial calcification, a condition where calcium builds up in the arteries, and maintain cardiovascular health, though further investigations are needed to fully test this theory across populations. 38

This review highlights water and fat-soluble vitamins' multidimensional role in supporting physiological, neurological, cardiovascular, and reproductive health. While some forms of supplementation, such as folate during gestation or vitamin D in populations with limited sun exposure, have proven helpful, routine intake should be approached cautiously as over-supplementation with fat-soluble vitamins may result in overeating and even lead to toxic side effects due to long-term storage in our bodies.

In summary, adequate levels of both water-soluble B vitamins and fat-soluble vitamins are necessary to promote overall wellness and avoid chronic disease. Their impact can differ based on genetics, age, lifestyle, and coexisting medical conditions, so adequate consumption should not only benefit but also prevent them. Future studies should explore optimal dosage, bioavailability, and long-term health outcomes associated with both deficiency and excess. Tailored nutritional interventions tailored to an individual's specific needs and risk profiles promise to optimize benefits while minimizing potential risks. Public health strategies must focus on education and guidance for creating diets rich with essential nutrients and informed supplement use throughout life.

This evidence review highlights vitamins' complex and multidimensional role in chronic disease prevention. While certain B vitamins—particularly folate, B6, and B12—show promising effects in lowering homocysteine levels and potentially decreasing risks of cardiovascular and neurodegenerative conditions, evidence from larger clinical trials remains mixed. Similarly, vitamin D does have biological plausibility with improved cardiometabolic and skeletal outcomes, but it hasn't demonstrated consistent preventive benefits in random controlled trials.

Fat-soluble vitamins like vitamins A, D, E, and K and carotenoids play an essential role in modulating immune responses, oxidative stress levels, and cell signaling pathways. Their supplementation outcomes vary based on dose, population characteristics, and baseline nutritional status; vitamin E's antioxidant benefits have not consistently translated to decreased cardiovascular or cancer risks when studied clinically while supplementing with beta carotene may cause harm among smokers; by contrast, consuming whole fruits and vegetables may confer additional protective benefits through synergistic interactions with bioactive compounds that act together on bioactive compounds within them thereby creating synergies which enhance their effects when taken orally dietary sources seem more protective benefits due to synergies with bioactive compounds present.

Overall, this review illuminates that while vitamin supplementation may provide targeted benefits in populations with confirmed deficiencies or elevated risk profiles, an indiscriminate one-size-fits-all approach does not support current evidence. Instead, more tailored, evidence-based strategies that emphasize balanced nutrition-rich diets over high-dose supplementation should be implemented. Furthermore, long-term clinical trials need to take place with diverse populations across chronic disease endpoints to more fully establish individual vitamins' preventive potential and effect.