21

Vitamin supplements are not demonstrably useful for healthy people taking a healthy diet It is worthwhile referring directly to some of the primary literature for this question (especially so since I was heavily criticised for selectively quoting the @david-hedlund answer above in another question Are Vitamins ingested in natural food more effective than ...


13

This is a complex issue. What the public health authorities are saying is correct. Vitamin supplements have health benefits for certain groups of people in certain instances and there are many studies to show this. Vitamin D and Calcium are often recommended for people at risk of osteoporosis. Some people may have digestive disorders for example that also ...


13

Breakdown of the claims There are a couple of claims contained together in this question. Vitamin D is formed on the skin (as well as in). Relatively large amounts remain on the skin or are secreted immediately from sun-sexposure onto the skin. In both cases the vitamins need an up to 48h waiting period to be (re-)absorbed by the body/skin. That washing ...


12

Pauling believed that large doses of vitamin C could achieve many health benefits and he was powerful and persuasive advocate of his theories. But his persuasiveness didn't sway the scientific consensus. One early (1976) review of the idea that the vitamin protects against the common cold reported this: A more recent American study of adult employees of ...


12

I was unable to find many studies dealing with vitamin B12 specifically as most studies deal with B vitamins in general. The studies I found indicate that B vitamins are not effective mosquito repellents. A 2002 study in the New England Journal of Medicine comparing the efficiency of different mosquito repellents reported that: No ingested compound, ...


11

In summary: There is not sufficient evidence to show that Vitamin D has a preventative effect on dental caries. It is plausible, and following the recommended intake of Vitamin D is important for a number of health reasons, but there is no solid evidence to show that it alone is adequate for the prevention of dental caries. Fluoride, on the other hand, has ...


7

TL;DR It depends on the vegetable, and what other preparation method you're comparing it to. A study in the Nov 2003 issue of Journal of the Science of Food and Agriculture (Paywall--some key points explained here). From the abstract: High-pressure boiling, low-pressure boiling (conventional), steaming and microwaving were the four domestic cooking ...


7

I would not worry. Most vitamins are very stable. Vitamin C can oxidize, a little, over about a week, but overall vitamins are retained in large percentages, over months, even at room temperature. More in particular, your question is very wide so I will only give a general answer based on this USAID study, but there are different reasons why vitamins ...


7

No. After this extremely short tl;dr: to be fair, we do not know for sure. Because it seems to be quite complex, if not complicated. And that means the claim is at least very dubious. 25 years ago Vitamin K metabolism would have only considered K1 (phylloquinone) and discuss its role in haemostasis. That has changed and the other derivates are now under ...


5

Possibly, but not likely There is an older study mentioned in this 1985 Chicago Tribune article that states that and extremely high dose of Vitamin C followed by eating shrimp may result in "trivalent arsenic" being converted from the compounds in shrimp. "What the Illinois researchers found is that high doses of vitamin C convert the pentavalent compounds ...


5

The air conditioner does not create the Vitamin C. Ascorbic Acid is stored in some kind of material, comes to the surface in a defined way, and is carried with the air. The filters / dispensers have to be replaced when they are empty. I could not find any references to the actual replacement parts. Some info about the Nissan system is here. Interestingly ...


4

Yes. Many studies show the evolution of vitamin in milk while heating. You may even compare heating methods. In this article, the evolution of B12 vitamin is drawn (figure 1). However, the loss of vitamin that occurs while heating the milk up to 100°C is only around 10% of the total B12 vitamin. Prolongated heating will really lower the concentration ...


3

Depends on the food-- Organic Tomatoes have more Vitamin C A large review in 2006 showed that different vegetables have different contents depending on the farming practices used (ie, organic vs non-organic). Most helpful here, including sources, is Table 2 of that study. In that table, the following statements describe the results of various fruits and ...


2

Update #1: http://www.ncbi.nlm.nih.gov/pubmed/17556807 Dark storage limited the decrease in juice asparagine to some extent. Aromatic lactones, such as gamma-decalactone and gamma-dodecalactone, both in skin and in flesh tissues increased more rapidly when the fruits were stored under a light condition, irrespective of fruit harvest stage. From these ...


2

No, it hasn't. A team led by Bravata, a senior affiliate with Stanford’s Center for Health Policy, and Crystal Smith-Spangler, MD, MS, an instructor in the school’s Division of General Medical Disciplines and a physician-investigator at VA Palo Alto Health Care System, did the most comprehensive meta-analysis to date of existing studies comparing ...


2

"According to Dr. Rath" reminded me of Linus Pauling and Matthias Rath's unified theory. Matthias Rath (born 1955 in Stuttgart, Germany) is a controversial doctor, businessman, and vitamin salesman. Linus Pauling (February 28, 1901 – August 19, 1994) was one of the most influential chemists in history and ranks among the most important scientists of the ...


2

Boiling vegetables does reduce vitamins, sometimes substantially. The method of boiling makes a difference: boiling thawed vegetables reduces Vitamin C more than boiling direct from frozen. Even the pan makes a difference: the 2000 study Vitamin C losses in some frozen vegetables due to various cooking methods includes the result: While boiling ...


1

According @Sklivvz' reference, vitamin C is typically the least stable vitamin. I found a Study on the Kinetics of Vitamin C Degradation in Fresh Strawberry Juices that reports halflife for storage at 8 °C of 4:47 and 5:36 h for juice prepared without and with additional sugar, respectively - I assume that the former number is more relevant for people ...


1

The work of Nakahara et al. concerning vitamins L1 and L2 being essential for lactation is considered refuted in the sense that others found multiple generations could be bred living on diets that are deficient of vitamins L1 and L2. See Milk: the Mammary Gland and Its Secretion, volume II at page 171 which cites to the following article as an example: ...


1

Emblica officinalis (of the family Euphorbiaceae) also known as Indian gooseberry in the form of fruits contain mostly carbohydrate with moderate fiber content and are rich in vitamin C, with some other unique bioactives. Emblica officinalis extract is Generally Recognized As Safe as a food additive by FDA. The effects listed below were noted in ...


1

Vitamin D supplementation at the level of 800 IU per day does not appear to be an effective treatment for Seasonal Affective Disorder in older women. "Winter depression" is properly known as "Seasonal Affective Disorder" (SAD) or "major recurrent depressive disorder with seasonal pattern". As the name suggests, it's recurrent depression that occurs and ...


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