The truth is that the supplement industry is by and large a scummy and fraudulent money sinkhole.
However, there are a few simple things that are worth taking — situationally dependent — to address common imbalances or deficiencies.
I try to eat fresh fish twice a week. But, as any of my fellow midwesterners understand, fresh seafood isn’t always feasible. I think it’s prudent to supplement with quality fish oil if you can’t get a few servings of omega-3 rich food per week. There is considerable scientific evidence supporting the notion of balancing your omega 3/6 ratio — learn more about that here. It’s very important to choose a quality brand. I recommend Carlsons. Don’t buy fish oil in bulk. Get a single 30 day supply at a time and keep it in the fridge and out of the light to ensure it stays fresh.
Vitamin D deficiency has gotten a lot of recent attention, and for good reason. Most first worlders, particularly those in less equitorial climates, are not getting enough sun on skin exposure, which is how we naturally synthesize vitamin D. If you’re not getting regular full body sun exposure to the tune of at least 30 minutes a day, then you should probably supplement vitamin D. I recommend a d3/k2 combo.
If you think you need supplementation to address some other insufficiency, I strongly recommend Examine.com’s supplement FAQ. They have, by far, the most objective and scientifically substantiated answers to common supplement questions. Start with the FAQ page and navigate from there.
And, of course, work with your doctor to actually address any potential nutritional shortfalls that may benefit from supplementation.