Vitamin A is a fat-soluble vitamin that is naturally present in many foods. Vitamin A can be differentiated into two groups. One is animal sources or retinol and the other are plant sources or provitamin A carotenoid, which can be converted into retinol in the body.
*Note: Non-provitamin A carotenoids include lutein, zeaxanthin, and lycopene, and have been associated with the risk reduction of macular degeneration, the leading cause of vision loss in Americans.
Vitamin A is important for vision, the immune system, reproduction, regulation, and maintenance of normal functions of the heart, lungs, kidneys, skin and mucous membranes, among other organs. A new study published in JAMA this year showed that dietary retinol and carotenoids might reduce the risk of squamous cell carcinoma (SCC). SCC is the second most common form of skin cancer with more than one million cases diagnosed in the U.S. each year.
According to this large prospective study that included over 120,000 individuals and a follow-up period of more than 26 years, higher intake of total vitamin A, retinol, and several individual carotenoids, including beta-cryptoxanthin, lycopene, and lutein and zeaxanthin, was associated with a lower risk of SCC. The results were generally consistent between men and women. The results show that retinol is essential for the maintenance building of healthy tissues and can reduce the formation of a tumor mass of undifferentiated cells, which might lead to cancer.
This study clearly demonstrates the benefits of getting vitamin A from natural food sources. Food sources for vitamin A include beef liver, fish oils, milk, eggs, leafy green vegetables (kale, spinach, broccoli), orange and yellow vegetables (carrots, sweet potatoes, pumpkin and other winter squash, summer squash), tomatoes, red bell pepper, cantaloupe, mango, and fortified foods.
More studies are needed to determine whether vitamin A supplementation has a role in reducing the risk of developing SCC. However, some studies have shown undesirable side effects when given big doses of beta-carotene supplements in different populations, such as an increased risk for lung cancer in smokers.
The recipe of the day comes via The Minimalistic Baker: Carrot Ginger Turmeric Smoothie
- 2 cups carrots
- 1 1/2 cups filtered water
- 1 large ripe banana (previously peeled, sliced and frozen; more for a sweeter smoothie)
- 1 cup frozen or fresh pineapple
- 1/2 Tbsp fresh ginger (peeled;1 small knob yields ~1/2 Tbsp)
- 1/4 tsp ground turmeric (or cinnamon)
- 1/2 cup carrot juice
- 1 tbsp lemon juice
- 1 cup unsweetened almond milk
- Make carrot juice by adding carrots and filtered water to a blender and blending on high until completely pureed and smooth. Add more water if it has trouble blending. Scrape down sides as needed.
- Drape a large, thin dish towel over a mixing bowl and pour over the juice. Then, lift up on the corners of the towel and begin twisting and squeezing the juice out until all of the liquid is extracted. Set aside pulp for smoothies, or baked goods (such as carrot muffins).
- Transfer carrot juice to a mason jar. Can keep for several days, though best when fresh.
- Add smoothie ingredients to the blender and blend on high until creamy and smooth. Add more carrot juice or almond milk if it has trouble blending. Scrape down sides as needed.
- Taste and adjust flavors, as needed, adding more banana or pineapple for sweetness, lemon for acidity, ginger for bite, and turmeric for warmth.
- Divide between two glasses and serve. Best when fresh.
Karen Alexander, MS, RDN, LD/N