Eli5: Why are multivitamins inferior to fruits/vegetables?

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Every article I read says you should primarily get your vitamins through fruits and vegetables and other whole foods rather than multivitamin pills. But if you look at the nutritional facts on say, a bag of spinach or cup of fruit, the % daily value seems way lower than a regular multivitamin, and you’d need to eat a ton of fruits/veggies to get a comparable intake (a single serving of spinach is usually almost an entire bag).

What am I missing?

In: Biology

16 Answers

Anonymous 0 Comments

There are some good answers here, I just want to highlight what science has found about supplements.

“Randomized controlled trials

Unfortunately, randomized controlled trials of specific supplements have failed to demonstrate a consistent or significant effect of any single vitamin or combination of vitamins on incidence of or death from cardiovascular disease (Morris and Carson 2003). Vitamin E plus vitamin C plus betacarotene showed no difference in all-cause, vascular, or nonvascular mortality, or secondary measures including major coronary events, stroke, revascularization, and cancer compared with placebo (Heart Protection Study Collaborative Group 2002). In a meta-analysis of 135 967 participants in 19 randomized controlled trials using vitamin E, nine of eleven trials showed an increased risk for all-cause mortality at a dose greater than or equal to 400 IU per day of vitamin E. No increase in all-cause mortality was seen for doses less than 400 IU per day in these trials, but a dose-response analysis showed that a statistically significant relationship between vitamin E dosage and all-cause mortality began at a dose greater than 150 IU/day (Miller et al 2005). A similar increase in mortality has been described in very high dose vitamin E (2000 IU per day) supplementation in persons with Alzheimer dementia (Sano et al 1997; Miller et al 2005).

Four placebo-controlled trials have not shown a benefit of betacarotene, alone or combination with alphatocopherol or retinol, or alphatocopherol alone on the development of lung cancer. For people with risk factors for lung cancer, no reduction in lung cancer incidence or mortality was found in those taking vitamins alone compared with placebo. For people with no known risk factors of lung cancer, none of the vitamins or their combinations appeared to have any effect. In fact, in combination with retinol, a statistically significant increase in risk of lung cancer incidence was found compared with placebo (Caraballoso et al 2003).

Table 2 summarizes examples of randomized controlled trials and meta-analytical reviews for vitamins and specific diseases. The data from randomized controlled trials show (with a few exceptions) that supplementation with vitamins has not had much effect on disease states. Vitamin D supplementation, along with calcium, has been demonstrated to reduce hip fracture rate in older persons. The use of mineral and vitamin supplements has been shown to slow the progression of, but not prevent, age-related macular degeneration. Folate may have some role in the treatment of depression, although the trials have been small in numbers. Vitamin C may, or may not, have an effect on hypertension, but the longest trials were only two months in duration. Six controlled trials on supplementation of vitamin C in persons with asthma showed no appreciable benefit on asthma outcome”

[this source has lots of good info](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2682456/)

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