Are you sad? I often am. Anyone with a genetic predisposition to depression knows what it’s like to have the blues for no earthly reason. And when you are an animal rights activist, it can make things a whole lot worse.

Let’s face it, when you care about animal suffering, it’s pretty easy to feel despondent and despairing. How many of us can read about factory farming or puppy mills or fur farms without feeling anger at the least, and more often a sense of overwhelming sadness.

Maybe we can’t change our genes or control all of the things in the world that make us unhappy. But lifestyle, including diet and exercise, can make a big difference. For example, vegans can be at higher risk for certain nutrient deficiencies that might affect mood.

Research suggests that low intakes of vitamin D, vitamin B12, and omega-3 fatty acids might lead to depression. For everyone—omnivores included—the only sources of vitamin D are supplements, fortified foods and sun exposure. (Actually, there are a few animal sources of vitamin D, but it is very unlikely that omnivores can eat enough of them to meet needs; that’s why cow’s milk is fortified.)

Getting enough vitamin D from sunlight is tricky because there are so many variables such as where you live, your age, and the level of pigmentation in your skin, not to mention the fact that sun exposure raises risk for skin cancer. Therefore, it is prudent for everyone to get some vitamin D from fortified foods or supplements. Vegans can look for supplements of vitamin D2 or ergocalciferol, which is plant-derived. The RDA is 600 IU per day.

All vegans need to supplement with vitamin B12, using either fortified foods or chewable supplements. You can find more information about this in my examiner column on B12.

Whether or not vegans need to supplement with the long-chain omega-3 fats (DHA) that are found in fish oils isn’t known since the research is conflicting. In the meantime, it might be a good idea for vegans to take around 200 micrograms per day of an algae-derived supplement. Jack Norris, RD has a list of vegan DHA supplements on VeganHealth.

For most people, taking supplements isn’t likely to cure depression. But a diet that is deficient in nutrients can definitely sabotage efforts to feel better. A well-balanced diet with appropriate supplements or fortified foods can help.