Vitamin A

It’s funny, the things that are considered lipids. But of course, when an entire class of compounds is defined by it solubility in water (rather than it’s biological function, for instance), you get funny things. Like fats and vitamin A being lumped together. Like vitamin E, vitamin A is a fat soluble vitamin.

There are several forms of vitamin A: preformed vitamin A (including retinol) from animal sources and pro-vitamin A (carotenoids like beta-carotene) from plant sources [1, 2]. In the human body, vitamin A becomes retinal and retinoic acid.

You might notice the “retina” in the names and be thinking about how your mom told you “Carrots are good for your eyes.” It’s true: vitamin A is essential to sight, especially night vision. Retinal attaches to a protein in your eye called rhodopsin and when light hits the retinal molecule, it changes shape. This leads to the rhodopsin protein changing shape, too, and that signals that there is light to see by [12].

Pro-vitamin A carotenoids are derived from plant pigments–the same ones that make those pretty fall colored-leaves–and this is what leads to that vegetable-induced glow. Besides that, topically applied vitamin A is associated with cell turnover, leading less inflammation and fewer blemishes [3]. Vitamin A is also important for a well-functioning immune system. This includes maintaining skin’s barrier function (you know your skin is your first line of defense against disease,right? Taking care of it is a top priority) [2].

Vitamin A, being fat-soluble, can cause problems both when you don’t get enough and when you get too much. However, this seems only to be a problem with preformed vitamin A–not beta-carotene [1]. So, no reason to skip out on the fruits and veggies!

Advertisements

Vitamin B5 (Pantothenic Acid)

The B vitamin complex is varied and certainly important. One of the many B vitamins is pantothenic acid (vitamin B5), an important part of Coenzyme A (CoA). CoA is known for its acetylation properties–most proteins with added acetate groups were modified by CoA, and this modification changes shape of the proteins (and thus the function). This is especially important for the replication of DNA [1].

Histones are positively charged proteins that our negatively charged DNA coils around. However, when these proteins are acetylated, they lose their positive charge, and the DNA coils less tightly. This relaxes the DNA and is associated with increased gene expression (Plain English Translation: we make more proteins for genes that come from relaxed DNA) [2, 3]. This can have huge repercussions for our bodies–it can change whether we produce the right amount of inflammatory proteins or antibodies, for instance.

Coenzyme A is also known for its role in metabolizing the macronutrients and their building blocks: fats, cholesterol, and fatty acids; proteins and amino acids; and carbohydrates. Even things like heme (as in hemoglobin, as in super important to red blood cells) require CoA, and thus vitamin B5, to produce them [1].

On a cosmetic level, vitamin B5 is an important ingredient for healthy skin by improving barrier function [4, 5] and healthy hair [6] by sealing the shaft (similar to how it improves skin’s barrier function).

Vitamin E

Vitamin E is a fat-soluble vitamin–or, rather, it’s a family of eight different compounds. Of these eight compounds, the most biologically significant is alpha-tocopherol. Note that sources may be listed as d-alpha-tocopherol or dl-alpha-topopherol. In this case d indicates a naturally derived source of vitamin E rather than a synthetic dl source and natural sources have been shown to be more powerful and are retained more by the body. Vitamin E is an important antioxidant and is especially associated with stable membranes because it stops the oxidation of lipids [1, 3].

Vitamin E has been shown to help with immune function–even decreasing chances of getting the common cold. It’s been correlated with better scores on cognitive tests in those without dementia and in slowing dementia’s progress in some patients. Symptomatic vitamin E deficiency has been linked to damage to the retina, implicating vitamin E in maintaining healthy eyes [1].

However, vitamin E is especially known for its effects on skin. Vitamin E is reported to have photo-protective effects, and in combination with vitamin C, it is even more effective, further decreasing DNA damage after sun exposure. In fact, vitamin E by itself (or with vitamin C) applied after sun exposure is still shown to help decrease inflammation and the extent of the burn [2].

There are some risks associated with getting too much vitamin E and the most prevalent are its anti-coagulant effects. However, most Americans do not even reach the threshold for the minimum recommended intake for vitamin E, so these worries apply only to those taking supplements with a high dosage. Good sources of vitamin E include olive oil, nuts, and leafy greens [1].

Resources

1. Vitamin E. Micronutrient Information Center. Linus Pauling Institute.

2. Vitamin E and Skin Health. Micronutrient Information Center. Linus Pauling Institute.

3. Vitamin E. Beautypedia Cosmetics Ingredient Dictionary.

Zinc

Zinc, a trace mineral, is an essential part of a healthy diet. We use it in our cells in enzymes and proteins, as transcription factors (used in the protein production and gene expression) and catalysts.

Zinc is necessary for our immune function, since it is integral to white blood cell function and production. Zinc has been linked to lowered levels and severity of acne (in part caused by Propionibacterium acnes, a bacteria), and this may be due in part to zinc’s part in immunity. However, the studies in this area have not reached consensus.

Zinc interacts with vitamin A, most notably by splitting retinol into retinal, a molecule in the protein rhodopsin which is responsible for sight. It may interact with folic acid. However, it isn’t all just sunshine and unicorns: zinc can decrease copper bioavailability. Plus, excess iron, calcium, and phytates (from phytic acid) can lower zinc’s bioavailability.

Because phytic acid can bind to zinc rendering it unable to be absorbed and animal foods providing some of the highest concentrations of zinc, vegetarians must be especially careful about this mineral. Vegetarians may need up to 1.50 times as much zinc as the standard omnivore.

Resources

Abstracts about zinc and acne, both from the National Institutes for Health, available here and here.

NIH Office of Dietary Supplements Zinc Fact Sheet for Health Professionals.

Jane Higdon, Ph.D. (2003). Zinc. Linus Pauling Institute, Oregon State University. Updated in 2013 by Emily Ho, Ph.D.

Vitamin C

Discovered due to it’s importance in preventing scurvy, the plague of sailors in the Age of Exploration, vitamin C is an essential element of a healthy diet. It acts as a cofactor in the production of a multitude of biologically important molecules, from collagen to dopamine.

Nowadays, scurvy isn’t as big an issue and vitamin C is valued for its efficiency and potency as an antioxidant. This water-soluble vitamin is actually such a good antioxidant that it recycles other antioxidants after these compounds are themselves oxidized.

Now, something this important sounds like something we should be able to manufacture ourselves, yes? For almost all animals, including most mammals, vitamin C can be manufactured by the organism itself. However, in some primates, including all humans, vitamin C must be acquired through diet.

In studies, both supplemental and dietary vitamin C have been shown to lower cardiovascular disease related deaths. Additionally, it can lower both LDL cholesterol (without effecting HDL) and blood triglyceride levels. That is nothing to sneeze at, since the Centers for Disease Control cites heart disease as the leading cause of death among American women, causing 1 in 4 women’s deaths.

What about vitamin C and the common cold? Studies have shown that in an otherwise healthy person, the common cold may be shorter in duration, but not in severity. Furthermore, taking vitamin C isn’t going to prevent getting the common cold (unless you are a bit deficient, in which case it will help).

Peppers, broccoli, kale, cabbage, peas, guava, and black currents are all better sources of vitamin C than citrus fruits. You can check out the list here.

Resources

 De Tullio, M. C. (2010) The Mystery of Vitamin CNature Education 3(9):48

Higdon, Jane. (2006) Vitamin C. Linus Pauling Institute. Updated November 2013 by Alexander J. Michels, Linus Pauling Institute Oregon State University.

Women and Heart Disease Fact Sheet from the Centers for Disease Control

Vitamin C and Immune Function. Abstract. Med Monatsschr Pharm. 2009 Feb;32(2):49-54; quiz 55-6.