The Role of Histamine in Mental Illness and Its Attenuation With Vitamin C – Part II
Vitamin C has been shown to protect the brain from drug-induced neurotoxicity (Shankaran, Yamamoto, & Gudelsky, 2001). Seniors with high vitamin C levels have better memory performance (Perrig, Perrig, & Stahelin, 1997). Another study concluded that retirees who supplemented with vitamin C had a lower rate of cognitive impairment (Paleologos, Cumming, & Lazarus, 1998). Vitamin C supplementation of 3 g/day reduced both state and subjective anxiety responses to psychological stressors (Brody, Preut, Schommer, & Schurmeyer, 2002). Vitamin C can reduce behavioral anxiety in animals (Brody, 2002).
Neuronal oxidative damage has been shown to be inhibited by vitamin C (Hediger, 2002). Vitamin C also protects against neuronal cell death by buffering glutamate-generated reactive oxygen species, known as ROS (Rice, 2000). The catecholamine neurotransmitters epinephrine, norepinephrine, and dopamine are easily oxidized, and oxidized catecholamines can be neurotoxic. Vitamin C inhibits metal ion-induced oxidation of catecholamines, and also detoxifies catecholamine degradation products (Gruenwald, 1993). Vitamin C inhibits glutamate-induced fast-firing neurons (Kiyatkin & Rebec, 1998), providing a protective effect against glutamate-mediated neurotoxicity.
Vitamin C inhibits dopamine-stimulated adenylate cyclase, even at low concentrations (it does not alter basal adenylate cyclase activity) (Thomas & Zemp, 1977). Adenylate cyclase produces cAMP. However, vitamin C does not inhibit norepinephrine-stimulated adenylate cyclase (Tolbert, Thomas, Middaugh, & Zemp, 1979). The above difference in adenylate cyclase interactions has important theoretical implications. Since high dopamine levels can cause psychosis, vitamin C inhibition of dopamine-stimulated adenylate cyclase may be the main mechanism of its neuroleptic-like action. By inhibiting dopamine-stimulated adenylate cyclase, vitamin C may be useful in treating dopamine-related disorders such as tardive dyskinesia, schizophrenia, and Huntington’s chorea (Tolbert, Thomas, Middaugh, & Zemp, 1979). Vitamin C also reduces many of the symptoms of the neurological illness Huntington’s disease (Rebec, Barton, Marseilles, & Collins, 2003).
There are a multitude of environmental pollutants that can lower vitamin C levels. Smoking, alcohol, steroids, analgesics, oral contraceptives, antidepressants, and anticoagulants can all reduce tissue and blood levels of vitamin C (Balch & Balch, 1997). Vitamin C deficiency can result in susceptibility to carbon monoxide, lead, and mercury poisioning (Vayda, 1994), since vitamin C plays an active role in detoxifying these chemicals. All three chemicals above are proven brain toxins. Vitamin C deficiency can lead to anemia, soft gums, capillary weakness, tooth decay, skin hemorrhages, loss of appetite, and muscular weakness (Hoffer & Walker, 1978). Not only does excess glucose cause a variety of chronic diseases, it also inhibits cellular uptake and accumulation of vitamin C in neutrophil immune cells (Washko, Rotrosen, & Levine, 1991).
Summary:
There are many reasons to supplement (megadose) with vitamin C in addition to improving and/or preserving mental health. White blood cell levels of vitamin C are only consistently raised with intakes of six grams or more daily (Janson, 2000). Vitamin C helps both cellular and humoral immune responses (Janson, 2000). Epidemiological studies have found that high plasma levels of vitamin C correlate with a death rate reduction of roughly 33% (Boeing & Rausch, 1996). Vitamin C appears to facilitate social interactions, since depletion of vitamin C in rats inhibited social behavior (Rebec & Wang, 2001).
Vitamin C attenuates subjective responses to psychological stress and also “reduces stress-induced cortisol release, and other indices of stress, including mortality following the stressor” (Brody, Preut, Schommer, & Schurmeyer, 2002, p. 320). Vitamin C can also improve mental health in more indirect ways. It is common knowledge that allergies and asthma are both physically and mentally irritating to people. People who doubled their vitamin C intake from 100 to 200 milligrams/day had 30% less bronchitis and/or wheezing (Feinstein, 1996). Vitamin C also partially blocks synthesis of inflammatory prostaglandins and leukotrienes (Feinstein, 1996).
There are a number of various food and vitamin interactions with both vitamin C and pharmaceutical antihistamines that are worth mentioning. Folic acid supplementation can raise histamine-related allergic symptoms (Pfeiffer, 1987). Therefore, people with allergies who supplement with a B-complex vitamin may want to take one which does not include folic acid. High copper can be both destructive to vitamin C and also can produce a pellagra-like mental illness (Pfeiffer, 1987). Again, people who take nutritional supplements, for example a