Does coffee increase anxiety? What research has been done on this subject?
There's a lot of studies/articles, but when it comes down to it it's just like any other "drug": it affects each person differently. I drink almost a pot a day, and have since I was around 17/18, and have no worsened conditions if I don't consume coffee. Some months I go with only a cup a day, and others its ~3-4 cups - and nothing changes drastically. As with anything else, especially "drugs", moderation is key.
This is, of course, anecdotal, so...
I think coffee can not increase anxiety but if you drink too much coffee, probably, you have been in a busy time. This means the stress of your life can increase anxiety. It's not related with coffee. However some people does not consider all the parameters related to their stress. Because they're used to their life and may judge the other stuff.
I only have anecdotal evidence. For me, coffee produces anxiety at first, until I acclimatize to a regular amount. For me, that's 2-4 cups a day. My body adjusts to that new "normal". I also exercise off any nervous edge coffee gives me.
In any case, I don't think coffee ever eases anxiety, even after you acclimatize. However, as a person with a tendency to be anxious, I can tell you regular exercise certainly does ease anxiety!
Niacin is present in coffee. According to one study entitled Synthesis and availability of niacin in roasted coffee:
The niacin content of weakly roasted commercial coffee is about 10 mg/100 g (American coffee) and it reaches 40 mg in heavy roasted coffees, i.e. Italian coffee. Caffeine-free coffee is lower in niacin than the corresponding raw coffee. The drinking retains 85% of the niacin formed during roasting; it is totally available for the organism and can constitute a noticeable part of the daily supply in niacin.
The Mayo Clinic has a page on niacin which describes the substance:
Niacin is a B vitamin that's made and used by your body to turn food into energy. It helps keep your nervous system, digestive system and skin healthy.
Niacin (vitamin B-3) is often part of a daily multivitamin, but most people get enough niacin from the food they eat. Foods rich in niacin include yeast, milk, meat, tortillas and cereal grains.
People use prescription niacin (Niacor, Niaspan) to help control their cholesterol.
While there are some articles linking niacin and depression, there does not seem to be any research linking the two. As Healthline concluded:
There still isn’t enough research to determine if vitamin B-3 is a good treatment for depression. Some personal stories, however, do support the idea that the vitamin can eliminate symptoms of depression.