The specifics of what we need every day to survive and what you should be getting from a daily calorie intake of around 2000 calories are:
Vitamin A – 5000 international units
Vitamin C – 60 mg (found in citrus fruits)
Calcium – 1000 mg (found in dairy products)
Iron – 18 mg (found in most red meat)
Vitamin D – 400 IU
Vitamin E – 30 IU
Vitamin K – 80 micrograms
Thiamin – 1.5 mg
Roboflavin – 1.7 mg
Niacin – 20 mg
Vitamin B6 – 2 mg
Folate – 400 micrograms
Vitamin B12 – 300 micrograms
Vitamin B5 – 10 mg
Phosphorus – 1000 mg
Iodine – 150 micrograms
Magnesium – 400 mg
Zinc – 15 mg
Selenium – 70 micrograms
Copper – 2 mg
Manganese – 2 mg
Chromium -130 micrograms
Molybdenum – 75 micrograms
Chloride – 3400 mg
All of these things are needed for us to function on tip top form. A deficiency in any one area can lead to serious issues in others. Most people get everything they need from their diets and if they know they’re lacking in any specific area there are various supplements available to balance this out again. This just illustrates the incredible variety of things we need to keep going. Human beings are immensely complicated organisms and though you’ll never need to know all of those things and exactly what they do, it’s always good to have an idea of just how complicated you actually are!