Can acidic foods interfere with the effectiveness of stimulants, such as Ritalin, Adderall, and Vyvanse? The question came up again at my face-to-face Silicon Valley Adult ADHD discussion group. So, let’s delve now into answering that question.
In a word, yes. Yes, food can interfere! Most specifically, an overly acid or alkaline system (ph) can affect some stimulants’ effectiveness. For example, citric acid or even antacids can mean the difference between a stimulant working—or not. This is important, because many Americans consume an extremely acid diet (e.g. soda, meat, cheese, chocolate, pasta, beer, wine, most grains, etc.); see image below.
But the cautions don’t stop with Ph. Even calcium or ammonium chloride, a food additive to bread and certain types of licorice, can reduce the stimulant effectiveness. Grapefruit juice has its own particular problematic interactions with stimulants and many other medications.
Unfortunately, many prescribing physicians remain unaware of these interfering factors.
Ph Spectrum: Acidic to Alkaline
Please keep in mind: There are many other explanations to explain why a stimulant medication fails—or ceases to work—for an individual. They include genetic and physiologic.
Right now, though, let’s view this issue primarily through the narrow lens of ph (alkalinity and acidity). Merriam-Webster defines ph this way:
a measure of acidity and alkalinity of a solution that is a number on a scale on which a value of 7 represents neutrality and lower numbers indicate increasing acidity and higher numbers increasing alkalinity and on which each unit of change represents a tenfold change in acidity or alkalinity and that is the negative logarithm of the effective hydrogen-ion concentration or hydrogen-ion activity in gram equivalents per liter of the solution; also: the condition represented by a pH number.
The image below gives you a clear idea of where everyday foods fall on the ph scale. In general, the idea is to aim for neutral, not too far one way or the other.
Case In Point: Citric Acid and Stimulant Absorption
Many years ago, I learned that citric acid can reduce the stimulant’s absorption—because it changes the ph of the gut. So, if someone complained to me of reduced effect from the medication, I would ask about any new habits around citric acid consumption. This might include drinking orange juice, eating certain fruits, taking a vitamin C supplement, or eating some other food product in which citric acid is added as a preservative. Examples of the latter include soft drinks, fruit-flavor candies, and even some cooking stock/bouillon.
The general rule, I’d heard: Do not consume citric acid an hour before or after taking the stimulant. (The same is sometimes said of a high-fat meal—to avoid it around the time you take stimulant medication, as it can reduce absorption.)
This webpage (Citric Acid in Foods) contains a list of foods that contain citric acid naturally or to which it is added. The list is bigger than you might think, including berries, preserves and jams, and mayonnaise that is made with lemon juice. With children, think gummy bears, “fruit” chews, and all the other candy masquerading as fruit items.
Then again, I’d also heard that this acid/absorption issue applies more to the immediate-release medications. It’s less of a risk with the novel delivery systems for extended-release stimulants such as Vyvanse and Concerta.
Another meeting attendee had heard that citric acid actually improves absorption. As it turns out, that’s not the case.
Moreover, many middle-aged folks with late-diagnosis ADHD—their guts suffering from years of scattershot eating habits and stress—are also taking antacids. Can that affect stimulant effectiveness, too? You bet.
Let’s start solving this puzzle by examining medication label inserts, textbooks, and published literature. Read on.
Paper Inserts Shed Some Light
I checked the label insert for various stimulants. They offered some information.
Basically, yes, the gut ph (alkalinity/acidity) can reduce absorption. But it seems to vary by delivery method. That is, the way the medication is delivered to the bloodstream. For example, Adderall, Concerta, Vyvanse, and Daytrana (the patch) are all delivered via different mechanisms.
- Acidifying agents:
- Gastrointestinal acidifying agents (guanethidine, reserpine, glutamic acid HCl, ascorbic acid, fruit juices, etc.) lower absorption of amphetamines.
- Urinary acidifying agent (ammonium chloride, sodium acid phosphate, etc.) increase the concentration of the ionized species of the amphetamine molecule, thereby increasing urinary excretion.
- Both groups of agents lower blood levels and efficacy of amphetamines.
- Alkalinizing agents
- Gastrointestinal alkalinizing agents (sodium bicarbonate, etc.) increase absorption of amphetamines. Coadministration of Adderall and gastrointestinal alkalizing agents, such as antacids, should be avoided.
- Urinary alkalinizing agents (acetazolamide, some thiazides) increase the concentration of the non-ionized species of the amphetamine molecule, thereby decreasing urinary excretion.
- Both groups of agents increase blood levels and therefore potentiate the actions of amphetamines.
Summary: A system that is too alkaline or acid will reduce medication effectiveness.
- Alkalinizing agents (GI antacids, including sodium bicarbonate, and urinary): These agents increase blood levels of amphetamine. (7.1)
- Acidifying agents (GI and urinary): These agents reduce blood levels of amphetamine. (7.2) One of these acidifying agents is ammonium chloride, also known as sal ammoniac; Wikipedia has this to say about ammonium chloride:
In several countries, ammonium chloride, known as sal ammoniac, is used as food additive under the E number E510, commonly as a yeast nutrient in breadmaking. It is a feed supplement for cattle and an ingredient in nutritive media for yeasts and many microorganisms.
Ammonium chloride is used to spice up dark sweets called salty liquorice (very popular in Nordic countries, especially in Finland), in baking to give cookies a very crisp texture, and in the vodka Salmiakki Koskenkorva for flavouring. In India and Pakistan, it is called “Noshader” and is used to improve the crispness of snacks such as samosas andjalebi
- Urinary acidifying agents may reduce blood levels of amphetamine. (7.1)
- Urinary alkalinizing agents may increase blood levels of amphetamine. (7.2)
[No ph interactions listed, perhaps because Daytrana is a methylphenidate patch worn on the skin and is not absorbed through the gut.]
- In patients, there were no differences in either the pharmacokinetics or the pharmacodynamic performance of CONCERTA® when administered after a high fat breakfast. There is no evidence of dose dumping in the presence or absence of food.
[The label makes no mention of ph interactions, perhaps due to Concerta’s novel delivery system.]
- Especially tell your doctor if you or your child takes stomach acid medicines.
- Antacids or acid suppressants could alter the release of Focalin XR
- The effects of gastrointestinal pH alterations on the absorption of dexmethylphenidate from Focalin XR have not been
studied. Since the modified release characteristics of Focalin XR are pH dependent, the coadministration of antacids or
acid suppressants could alter the release of dexmethylphenidate.
The Literature Tells Us This
Next, I checked the literature (not an exhaustive search at this point) and found this information:
- The Medical Basis of Psychiatry: Both citric acid and calcium can affect stimulant absorption; offers no details on how the various delivery systems might differ.
- One paper (Lisdexamfetamine Dimesylate (Vyvanse), A Prodrug Stimulant for Attention-Deficit/Hyperactivity Disorder) offers information about Vyvanse that, if I’m reading this correctly, seems to contradict the official information:
In an in vitro study, the pH-solubility profile of LDX was determined in buffered aqueous solutions using an assay specific for LDX.
The environmental pH did not affect the solubility profile of LDX within the biological pH range (pH, 1–8), suggesting that gastric pH variation does not affect the absorption of LDX.
Due to the effect pH has on absorption, amphetamine also interacts with gastric acid reducers such as proton pump inhibitors and H2 antihistamines, which increase gastrointestinal pH (i.e., make it less acidic).
Grapefruit Presents Particular Challenges
Now consider a very particular type of citrus: grapefruit. Beyond any considerations about acid and Ph, grapefruit—both the fruit and the juice—can create adverse outcomes when taken with certain medications, including some stimulants. The culprit seems to be flavonoids called furanocoumarins.
Wikipedia has a very clear entry on this topic, excerpted here:
One is that grapefruit can block the hepatic CYP3A4 thereby affecting the medication metabolism. If the drug is not metabolized, then the level of the drug in the blood can become too high, leading to an adverse effect.
On the other hand, if the medication is provided as a pro-drug [Gina notes: Vyvanse is a pro-drug], compromising its metabolism may prevent the drug from being created, thereby reducing its therapeutic effect.
The other effect is that grapefruit can block the enterocyte CYP3A4 thereby affecting the medication absorption in the intestine. If the medication is absorbed to a lesser extent, it may not reach a therapeutic level and its effect may be compromised.
In other words, grapefruit juice can be a problem in two big ways:
1. Create a toxic too-high dose of the medication
2. Reduce the medication’s therapeutic effect.
For more information on cytochrome P450, check this post from the series I wrote with my molecular-biologist husband: Part 4: Gene-Testing to Inform ADHD Drug Therapy.
The list of grapefruit’s potential drug interactions is long. Here is a sampling, again from the Wikipedia entry on Grapefruit-drug interactions:
- All the stimulant medications
- SSRI antidepressants
- Anti-Erectile Dysfunction medications
The Bottom Line
It should be clear, from this brief examination, that ph can be a factor in stimulant efficacy. Grapefruit juice has its own particular effect on absorption of stimulants and other medications. We also touched briefly upon the role of calcium, fat, and food additives such as ammonium chloride.
This is a reminder that stimulants do not act in a vacuum. They act in a highly individual human body. In order to be most effective, the stimulants require physiological support, including but not limited to:
- Adequate sleep: Stimulants cannot compensate for sleep deprivation
- Good nutrition: All medication targeting neurochemicals need “helpers”—B vitamins, potassium, magnesium, and other vitamins and minerals that help to fuel neural transmission (“moving messages around”).
- Adequate protein: Not “high protein” but rather adequate—because proteins are composed of amino acids. Amino acids are the building blocks of neurotransmitters such as dopamine, serotonin, and the like.
What’s Your Experience?
I’d love to hear your experiences on this topic. For example:
- Have you noticed that taking an antacid creates problems with your stimulant being effective?
- Did your physician ever mention these factors? If so, what information was provided?
- If you have particular knowledge in this area, please write a comment and I will incorporate into this post for future readers to benefit. Thanks.