Premenopause, or perimenopause, can start to rear its head when you reach age 40. During this period before menopause, which can last as many as 10 to 13 years, women may experience a variety of uncomfortable symptoms including mood swings, anxiety, depression, irritability and weight gain. But don't despair. Working with your doctor, you can create a plan to ease the symptoms you're experiencing and feel great into your 40s and 50s. Getting enough of certain vitamins from a healthy diet or supplements is key. The best vitamins for perimenopause are vitamins D, K, E and the B vitamins.

Get Enough Vitamin D

Termed the sunshine vitamin because it's synthesized by your skin when it's exposed to sun, vitamin D is an especially important nutrient to stock up on as you approach menopause. As you age, your skin's ability to synthesize vitamin D decreases, so you may be more prone to deficiency, especially because vitamin D is found naturally in very few foods. Vitamin D plays a crucial role in healthy mood. In fact, in an article published in "Journal of Midwifery & Women's Health" in 2008, lactation consultant Pamela K. Murphy and Dr. Carol L. Wagner report that studies show an increased risk of mood disorders among women with low vitamin D levels 23. The recommended daily allowance for women is 15 micrograms, and the best food sources are cod liver oil; fatty fish such as salmon, mackerel and tuna; and fortified products such as orange juice, milk and cereal.

Stock up on Vitamin K

You begin to lose bone mass after the age of 35, and women over the age of 50 have the highest risk of developing osteoporosis, a condition characterized by weak, brittle bones. Therefore, it's important to begin to increase your store of nutrients that support bone health during the premenopausal years. According to menopause expert and author Ellen Dolgen, one particular type of vitamin K, called MK-7, is especially important for premenopausal women because it helps prevent osteoporosis 4. A study published in September 2013 in "Osteoporosis International" supports this claim. In their three-year study, the researchers found that supplementation with MK-7 slowed the decline of bone mineral density and bone strength in a group of postmenopausal women 5. The RDA for vitamin K for women is 90 micrograms; MK-7 is a specific type of supplement, but you can also get vitamin K by eating kale, Swiss chard, broccoli, spinach and olive oil.

Ensure Adequate Vitamin E

Nutritionist Dr. Marilyn Glenville recommends vitamin E to help ease the discomfort of hot flashes, a symptom that some women begin to experience in perimenopause 6. In a study published in "Gynecologic and Obstetric Investigation" in July 2007, a group of menopausal women were given either a placebo or 400 international units of vitamin E for a four-week period 7. When taking the vitamin E, the women experienced statistically significant differences in the severity and frequency of their hot flashes 7. The RDA for women is 15 milligrams. Rich food sources of vitamin E include almonds, peanuts, sunflower oil and canola oil.

Increase Your Intake of B Vitamins

The B vitamins help regulate your metabolism and energy, and they also play a role in regulating your mood, fluctuations in which can greatly affect the quality of life of premenopausal women. According to a review published in "The American Journal of Clinical Nutrition" in June 2010, a deficiency in the B vitamins, especially B-12 and folate, is linked with depression. If you take an antidepressant, a deficiency can also affect how well it works, say the authors of the review. The RDAs for B-12 and folate are 2.4 micrograms and 400 micrograms, respectively. Rich sources of B-12 include clams, mussels, mackerel, beef and salmon. Folate is abundant in lentils, chickpeas, asparagus and spinach. Strict vegetarians should speak to their doctor about taking a B-12 supplement because B-12 is not present in plant foods.