Tyrosine vs Tyramine

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Foods to avoid on MAOIs

Micromedex Inc. - Vol. 82 Exp. 12/94

Tyramine is an amino acid which is found in various foods, and is an indirect

sympathomimetic that can cause a hypertensive reaction in patients receiving

MAOI therapy. Monoamine oxidase is found in the gastrointestinal tract and

inactivates tyramine; when drugs prevent the catabolism of exogenous

tyramine, this amino acid is absorbed and displaces norepinephrine from

sympathetic nerve ending and epinephrine from the adrenal glands. If a

sufficient amount of pressor amines are released, a patient may experience a

severe occipital or temporal headache, diaphoresis, mydriasis, nuchal

rigidity, palpitations, and the elevation of both diastolic and systolic

blood pressure may ensue (Anon [1989]; Da Prada et al [1988]; Brown &

[1988]). Therefore, dietary restrictions are required for patients receiving

MAOIs. Extensive dietary restrictions previously published were collected

over a decade ago and due to changes in food processing and more reliable

analytical methods, new recommendations have been published (Anon [1989];

McCabe [1986]). The tyramine content of foods varies greatly due to the

differences in processing, fermentation, ripening, degradation, or incidental

contamination. Many foods contain small amounts of tyramine and the formation

of large quantities of tyramine have been reported if products were aged,

fermented, or left to spoil. Because the sequela from tyramine and MAOIs is

dose-related, reactions can be minimized without total abstinence from

tyramine-containing foods. Approximately 10 to 25 mg of tyramine is required

for a severe reaction compared to 6 to 10 mg for a mild reaction. Foods that

normally contain low amounts of tyramine may become a risk if unusually large

quantities are consumed or if spoilage has occurred (McCabe [1986]). Three

lists were compiled (foods to avoid, foods that may used in small quantities,

and foods with insufficient evidence to restrict) to minimized the strict

dietary restrictions that were previously used and improve compliance and

safety of MAOI therapy. The foods to avoid list consists of foods with

sufficient tyramine (in small or usual serving sizes) that would create a

dangerous elevation in blood pressure and therefore should be avoided (McCabe

[1986]).

Foods to Avoid

Alcohol Avoid Chianti wine and vermouth. Consumption of red, white, and port

wine in quantities less than 120ml present little risk (Anon [1989]; Da Prada

et al [1988]; McCabe [1986]). Beer and ale should also be avoided (McCabe

[1986]), however other investigators feel major US brands of beer are safe in

small quantities (<120 ml) (Anon [1989]; Da Prada et al [1988]), but imported

beer should not be consumed unless a specific brand is known to be safe.

Whisky and liqueurs such as Drambuie and Chartreuse have caused reactions.

Alcohol-free beer and wines may contain tyramine and should be avoided (Anon

[1989]; Stockley [1993]).

Banana peel A single case report implicates a banana as the causative agent,

which involved the consumption of whole stewed green banana, including the

peel. Ripe banana pulp contains 7 mcg/gram of tyramine compared to a peel

which contains 65 mcg/gram and 700 mcg of tyramine and dopamine, respectively

(McCabe [1986]).

Bean curd Fermented bean curd, fermented soya bean, soya bean pastes contain

a significant amount of tyramine (Anon [1989]).

Broad bean (fava) pods These beans contain dopa, not tyramine, which is

metabolized to dopamine and may cause a pressor reaction and therefore should

not be eaten particularly if overripe (McCabe [1986]; Anon [1989]; McCabe

[1986]; Anon [1989], Anon [1989]; McCabe [1986]) and vacuum-packed pickled

fish or caviar contain only small amounts of tyramine and are safe if

consumed promptly or refrigerated for short periods; longer storage may be

dangerous (Anon [1989]). Smoked, fermented, pickled (herring) and otherwise

aged fish, meat, or any spoiled food may contain high levels of tyramine and

should be avoided (Anon [1989]]; Anon [1989]).

Protein extracts Three brands of meat extract contained 95, 206, and 304

mcg/gram of tyramine and therefore meat extracts should be avoided (McCabe

[1986]). Avoid liquid and powdered protein dietary supplements (Anon [1989]).

Meat, nonfresh or liver No detectable levels identified in fresh chicken

livers; high tyramine content found in spoiled or unfresh livers (McCabe

[1986]). Fresh meat is safe, caution suggested in restaurants (Anon [1989];

Da Prada et al [1988]).

Sausage, bologna, pepperoni, and salami contain large amounts of tyramine

(Anon [1989]; Da Prada et al [1988]; McCabe [1986]). No detectable tyramine

levels were identified in country cured ham (McCabe [1986]).

Sauerkraut Tyramine content has varied from 20 to 95 mcg/gram and should be

avoided (McCabe [1986]).

Shrimp paste contains a large amount of tyramine (Anon [1989]).

Soup should be avoided as protein extracts may be present; miso soup is

prepared from fermented bean curd and contain tyramine in large amounts and

should not be consumed (Anon [1989]).

Yeast, brewer's or extracts Yeast extracts (Marmite) which are spread on

bread or mixed with water, brewer's yeast, or yeast vitamin supplements

should not be consumed. Yeast used in baking is safe (Anon [1989]; Da Prada

et al [1988]; McCabe [1986]).

Foods to use with caution