These factors reduce your thiamine levels

Those who find that thiamine (vitamin B1) reduces their stuttering may be interested in the following list, mailed to me by an expert, of factors that reduce thiamine levels in the body.

If you find that more thiamine improves your fluency, it makes sense to try and avoid depleting the thiamine in your body where possible - though of course this should be weighed up against the positive effects these factors may have on other aspects of health.

For more information on thiamine/magnesium and their possible impact, if any, on stuttering, read this FAQ. Health Warning: Never take any food supplement without first consulting your medical practitioner. 

 Here is an exhaustive list of substances and other factors that can affect thiamine utilisation negatively:

Thiamine deficiency can occur when excess vitamin B1 is used up by the body. This can be caused by:

• Pregnancy
• Hyperthyroidism
• Lactation
• Fever - severe infection/sepsis
• Increased physical exercise; and
• Refeeding syndrome (a metabolic complication that occurs when nutritional support is given to severely malnourished patients).

Inadequate thiamine intake can also occur via diets consisting mainly of the following:

• Food containing a high level of thiaminases (which impair thiamine), including certain raw freshwater fish, raw shellfish, and ferns. When buying rice, try to get brown rice, as white rice has been milled, which means that most of the thiamine in the rice has been removed.
• Substances high in anti-thiamine factors, such as coffee, tea and betel nuts (it is not just the caffeine in coffee and tea that impacts on thiamine - the tannins in these products also work against thiamine. So also avoid decaffeinated tea and coffee, rather take herbal tea such as rooibos tea.) 
• Sulfites are added to many processed foods as a preservative. Sulfites destroy thiamine.
• Foods that are high in simple carbohydrates (in candies, cakes, syrups, sugar, fizzy drinks and others).

Alcohol consumption blocks thiamine assimilation and also injures the small intestine and reduces its ability to absorb thiamine. Smoking also has a negative effect on thiamine.

Certain medications can deplete vitamin B1. These include:

Acid blockers: cimetidine (Tagamet), esomeprazole (Nexium), famotidine (Pepcid and Pepcid Complete), lansoprazole (Prevacid 24hr), nizatidine (Axid), omeprazole (Prilosec OTC), pantoprazole (Protonix), rabeprazole (Aciphex) and ranitidine (Zantac).

Antacids: Aluminum & magnesium hydroxide (Maalox, Mylanta), aluminum carbonate gel (Basaljel), aluminum hydroxide (Amphojel, AlternaGEL), calcium carbonate (Rolaids, Titralac, Tums, Digestif Rennie), magnesium hydroxide (Phillips’ Milk of Magnesia) and sodium bicarbonate (Alka-Seltzer, baking soda).

Antibiotics (just a few listed here, but all deplete vitamin B1):

Aminoglycosides, amoxicillin (Amoxil), azithromycin (Z-pak), cefdinir (Omnicef), cephalexin (Keflex), ciprofloxacin (Biaxin), doxycycline (Doryx), erythromycin (E.E.S.), levofloxacin (Levaquin), minocycline (Minocin), penicillin (Pen VK), sulfamethoxazole and trimethoprim (Bactrim, Septra) and tetracycline (Sumycin).

Anticonvulsants: phenytoin (Dilantin) - space supplement at least 4 hours away from the medication; zonisamide (Zonegran).

Antivirals: delavirdine (Rescriptor), lamivudine (Epivir), nevirapine (Viramune), foscarnet (Foscavir), zidovudine, AZT (Retrovir), zidovdine and lamivudine (Combivir).

Aromatase inhibitors for breast cancer: anastrozole (Arimidex).

Cardiac glycoside: digoxin (Lanoxin, Lanoxicaps and Digitek).

Blood pressure drugs: bumetanide (Bumex), ethacrynic acid (Edecrin), furosemide (Lasix), torsemide (Demadrex), indapamide (Lozol), hydrochlorothiazide or HCTZ (Hyrodiuril). Any combination drug that contains HCTZ or hydrochlorothiazide (dozens of drugs contain this), chlorothiazide (Diuril), chlorthalidone (Hygroton), methyclothiazide (Enduron) and metolazone (Zaroxolyn).

Diuretics: loss of thiamine through renal excretion can occur with most, if not all, diuretics. It has been seen with the use of such diuretics as mannitol, acetazolamide, chlorothiazide, amiloride and loop diuretics. Thiamine loss is associated with the increase in urine flow rate.

Bronchodilators: theophylline (Uniphyl, Theo-24 or Theo-dur).

Hormone replacement therapy/oral contraceptives: estradiol (Estrace, Climara, Estraderm, Estring, Activella, Femring, Combipatch, Strogel, Menostar and many others), estrogen-containing drugs (hormone replacement therapy and birth control), conjugated estrogens (Premphase, Pempro) and ethinyl estradiol (found in many birth control pills).

Sulfonamides: sulfa antibiotics, some diabetes medications.

ERMs (selective estrogen receptor modulators used for breast cancer): raloxifene (Evista), tamoxifen (Nolvadex) and toremifene (Fareston).