Every winter, coaches are baffled when illness cripples their best athletes and most consistent dieters. The general public has come to accept this as a natural winter phenomenon, but hard training athletes are not part of the general public and cannot afford to spend a week drinking chicken soup and watching daytime television.

Whether sidelined by disease or tissue damage, recovering from a non-training induced stress or incident as quickly as possible is crucial to both the coach and athlete. Athletes, however fit they are, must accept the fact that their intensive training leaves them somewhat immunosuppressed, as well as more likely to experience acute trauma to their bones and tissues than their sedentary peers. By ensuring that their athletes have proper levels of Vitamins A and C, the coach can preemptively buffer the immune system of an athlete to keep illness, and lost training time, at bay.

Vitamin A

Vitamin A is the broad term for a large number of related compounds, though retinol and retinal are often referred to as ‘pre-formed” vitamin A. Beta-carotene and other carotenoids that can be converted by the body into retinol are referred to as “provitamin A carotenoids”. Literally hundreds of different carotinoids are synthesized by plants, though only about 10% are pro-vitamin A carotinoids.

Retinoic acid and its isomers can act as hormones to affect gene expression, subsequently having a wide range of influences at a baseline physiologic level. It is likely that vitamin A, vitamin D and thyroid hormone dynamically interact to influence gene transcription, which facilitates the specialization of cells for highly specific physiologic roles. This includes a significant role in wound and tissue healing or regeneration. Many of the physiological effects linked to vitamin A function appear to result from this role in cellular differentiation.

Vitamin A is also commonly regarded as the anti-infective vitamin because it is required for normal functioning of the immune system. Retinol and its metabolites are well known to maintain the function and integrity of the skin and mucosa, which serve as a first line of defense against infection. Several studies in animal models have documented the beneficial effects of optimal vitamin A intake on wound strength and strength of tendon repairs after surgery. Some authors have gone so far as to regard Vitamin A deficiency as a nutritionally acquired immunodeficiency disease.

Vitamin A has a critical role in red blood cell production. Precursor stem cells are dependent on vitamin A retinoids for normal differentiation into healthy red blood cells. Vitamin A also appears to facilitate the mobilization of iron from body storage sites to forming red blood cells for incorporation into hemoglobin molecules (the oxygen-transporting molecule in red blood cells).
A number of animal studies document the enhanced strength of skin wounds and bone with targeted vitamin A protocols. Levinson, et al suggest that vitamin A benefits healing most by enhancing the early inflammatory phase, including increasing the number of monocytes and macrophages at the wound site, modulating collagenase activity, supporting epithelial cell differentiation, and improving localization and stimulation of the immune response.

With the above in mind, form-ratios and targeted levels of vitamin A as optimized for the athlete will strongly support:
· normal gene expression,
· immune function
· iron / red blood cell / hemoglobin metabolism,
· ideal biomechanics, strength and compliance of integumentary tissue (skin, fascia, connective tissue)

Vitamin A dosing recommended for the athlete: 5000IU required retinol (as retinyl acetate) limited to an optimal 750IU (15%), combined with 4250IU (85%) of beta-carotene.

Vitamin C

Ascorbic acid, better known as vitamin C, is a water soluble vitamin that humans require through dietary sources. This is of particular interest, as humans are unlike most mammals that are able to produce their own vitamin C systemically.
Vitamin C is critical in the synthesis of collagen, a ubiquitous structural component of connective tissue, ligaments, tendon, bone, cartilage, capillary walls and blood vessels. Vitamin C has a very important role in tissue healing after injury or non-injurious trauma caused by athletic training.

Vitamin C also plays a role in the synthesis of norepinephrine, an important neurotransmitter critical to brain and nerve function. Additionally, vitamin C is required for the human body to synthesize carnitine, a molecule that is required for energy conversion by means of transport of fat to intracellular mitochondria.

Vitamin C is also known to function as an antioxidant, even in low doses. This action protects healthy tissue and cells from injury by the by products of normal metabolism or as generated through exposure to toxins, medicines, pollutants and other similar substances.

Vitamin C has a wide range of established clinical effects to include vasodilation effects, decreased hypertension, and mitigation long-term effects in diabetes. Several studies have provided evidence that wound healing in subjects not deficient in vitamin C can be accelerated with supplement levels above that as recommended for routine daily intake by the FDA.
The minimum RDA for vitamin C continues to be based primarily on prevention of deficiency disease, with little regard to chronic disease issues as outlined above. A minimum RDA for an adult is on the order of 75mg/day, though most supplements provide levels in comfortable excess (appreciating that tolerable safe upper limits are in the 1800mg/day range and above for adolescents and adults).

Forms and levels of vitamin C as optimized for the athlete will support:
•Best healing of bone, tendon, ligament, skin, capillaries and vessels, and other collagen-rich tissues, with recognition that there is a very wide margin of safety for this water soluble vitamin.
•Protective antioxidant effects and their potential benefits on recovering tissues.
Vitamin C intake recommended for the surgical patient: 400mg/day.

Vitamin D3

Vitamin D is a fat-soluble vitamin that is essential for maintaining normal calcium metabolism. Cholecalciferol, vitamin D3, can be synthesized in the skin upon exposure to sunlight.

Vitamin D is well known for its role in efficient calcium utilization and regulation in the body, and maintenance of serum calcium levels within a tightly controlled range is critical for normal nervous system function, bone growth, and maintenance of proper bone density.

Vitamin D is also important as an inhibitor of cell proliferation, and a supporter of cell differentiation. These effects have been studied observationally with respect to prevention of certain types of cancer; early promising results have prompted even more rigorous and controlled studies, which are ongoing presently. These effects on cell proliferation (division) and differentiation (specialization) also bear important implications for adequate vitamin D levels when it comes to optimizing conditions for wound or tissue healing.

Vitamin D is an important modulator of immune system function, particularly with respect to the cellular mediated responses. Most of the cells of the immune system (to include T-cells, macrophages, dendritic cells, etc) express the vitamin D receptor. There is a growing body of scientific study to support the importance of vitamin D in enhancing innate immunity and inhibit the development of autoimmunity. This potential for enhancing immune function also has clear importance as relative to recovery.
Adequate intake has been defined by the Food and Nutrition Board of the Institute of Medicine to be in the range of 200-600IU per day, depending on age and gender. These 1997 adequate intake levels are felt by most experts to still be far too low to appreciate best potential benefit of this vitamin. This has been progressively supported by evolving study, leading most experts (including the American Academy of Pediatricians and others) to recommend significantly higher daily intake of vitamin D.

Most present supplements contain vitamin D3 (cholecalciferol), which is more biologically potent than vitamin D2 (ergocalciferol).

Levels of D3 is the optimal form for athletes. Optimal dosing for the athlete requires appreciation that the most relevant literature supports an adult or adolescent intake level of at least 2000 IU / day in a normal state. Even higher levels have shown benefit in certain sub-groups of patients in observational studies (diabetes, some cancers, risk of fracture from osteoporosis, multiple sclerosis). Athletes have unique demands that would support intake in excess of 2000 IU per day.
Note that toxicity typically requires extremely high levels of vitamin D, with some experts suggesting 40,000 IU per day as a benchmark level of concern. Research published since 1997 suggests that the upper intake level is overly conservative and that vitamin D toxicity is highly unlikely in healthy people at intake levels less than 10,000 IU per day.
Vitamin D recommended for the athlete: Vitamin D3 (cholecalciferol): 1000-5000 IU/day

Vitamin K1 & K2

Vitamin K is a fat-soluble group of vitamins with primary effect as related to protein functioning in the normal clotting cascade, though the vitamin K family has a much broader range of effects that extend well beyond those related to blood clotting. There are two broad forms of vitamin K: vitamin K1 and vitamin K2. Vitamin K2 is synthesized by bacteria in a range of forms, while vitamin K1 is synthesized primarily by plants as phylloquinone. Phylloquinone represents the major dietary form of vitamin K, and has effects that are distinct from the effects of vitamin K2. The main role of vitamin K1 is in clotting and in reparative cell growth. The primary role for vitamin K2 is in cell growth and in bone mineralization, as well as other actions. Overt vitamin K1 deficiency can result in impaired coagulation with increased bleeding times. Fortunately, this is not common. The role for vitamin K2 with respect to osteoporosis, fracture healing and bone metabolism is rapidly evolving, with markedly increasing clinical application for fracture treatment and prevention in Europe and Japan.

Most clinical experts recommend a diet to include a regular and non-variable daily intake of vitamin K as a best strategy to safely balance the potential difficulties with excessive vitamin K against the known important advantages of an adequate daily oral intake of vitamin K1 and K2 (to promote bone mineralization and reparative cell growth). These vitamin K effects have particular importance after reconstructive orthopedic and spinal procedures, especially with surgery or joint implants requiring bone in-growth or bone healing. This same advantage is necessary for those athletes wanting to improve the strength of their boney structures to support weight lifting.

Although vitamin K is a fat-soluble vitamin, the body has little potential for vitamin K storage, so regular, consistent daily intake is required to support its role in bone healing and cell growth. Finally, the human body’s inability to store vitamin K is exaggerated further when patients are taking warfarin, as warfarin itself disrupts the body’s vitamin K recycling system.

The above balanced goals in mind, most clinical experts presently recommend:

· A relatively constant and non-variable daily dietary supplement intake of vitamin K1 and K2 to support reparative cell growth and bone mineralization
· Achieving the above with vitamin K amounts that are tailored to meet the higher demands as specific to training, particularly bone and joint procedures.

Vitamin K recommended for the athlete:
K1 = 500mcg/day
K2 = 5-15mcg/daily (preferably as MK-4, menatetranone)

The above important goals are best met by a directed, pharmaceutically-pure vitamin K1 & K2 supplementation program that will provide a predictable, stable daily dose of vitamin K, in conjunction with a patient recommendations for non-excessive, consistent volume, once a day whole-food intake of leafy greens (i.e. one salad of consistent size, once a day).