Clinical trails with varying doses of ascorbic acid showed that ascorbic acid does not have significant prophylactic effect, but reduced the severity and duration of symptoms of cold during the period of infection.
Consumption of ascorbic acid as high as 1 g a day for several winter months, had no consistent beneficial effect on the incidence of common cold.
There was a consistent beneficial but generally modest therapeutic effect on duration of cold symptoms.
In trials that tested vitamin C after cold symptoms occurred, there was some evidence of greater benefits with large dose than with lower doses.
An enterotype is a classification of living organisms based on its bacteriological ecosystem in the gut microbiome. Humans can be roughly divided into three enterotypes depending on which genus of bacteria dominates their gut: Bacteroides, Ruminococcus, or Prevotella.
- People who eat a lot of meat and saturated fat tended to have more Bacteroides in their flora.
- Ruminococcus prevailed in people who consumed lots of alcohol and polyunsaturated fats.
- Prevotella favored a diet rich in carbohydrates.
Long-term diet is strongly associated with the gut microbiome composition. If switching gut enterotype is possible, it may take a long-term dietary intervention.
Chimpanzees have enterotypes that are compositionally analogous to those found in humans.