Flaxseed is one of the world's oldest crops. There are two types, brown and golden, both of which are equally nutritious (1Trusted Source). Just one serving provides a good amount of protein, fiber, and omega-3 fatty acids, along with several important vitamins and minerals. One tablespoon (7 grams) of ground flaxseed contains (2Trusted Source): Calories: 37 Carbs: 2 grams Fat: 3 grams Fiber: 2 grams Protein: 1.3 grams Thiamine: 10% of the Daily Value (DV) Copper: 9% of the DV Manganese: 8% of the DV Magnesium: 7% of the DV Phosphorus: 4% of the DV Selenium: 3% of the DV Zinc: 3% of the DV Vitamin B6: 2% of the DV Iron: 2% of the DV Folate: 2% of the DV Flaxseed is particularly high in thiamine, a B vitamin that plays a key role in energy metabolism as well as cell function. It's also a great source of copper, which is involved in brain development, immune health, and iron metabolism