How much aluminum is in your food, or in products (which would allow for aluminum to be absorbed through the skin) such as deodorant? When most people think about aluminum, food sources are most likely not to come to mind, but rather, aluminum foil or aluminum pots. However, up to 10 mg of aluminum/day is ingested from freshly-prepared natural sources, mainly fresh fruit, vegetables and meat. Taking into account data from a US food additives survey, Greger (1993) estimated that approximately 50% of Americans ingest up to 24 mg aluminum/day, 45% ingest between 24 and 95 mg aluminum/day, and 5% take in more than 95 mg aluminum/day. The higher dietary aluminum range is likely accumulated from its presence in baking powder, as additives in commercially-processed foods and beverages and, from cooking with aluminum pots.

So, why is aluminum intake important? Is there an association with lifespan? The short answer is no. No effect on lifespan was shown by Walton (2007) when diets containing low, intermediate or high doses of aluminum (that in humans would be equivalent to 20, 25 or 85 mg/day for a 120 lb. woman, and 29, 36 or 122 mg/day for a 160 lb. man) were supplemented to rats, starting in middle age (16 months) forward in rats. Rats on the control diet lived, on average, 31.3 months; lifespan of rats on the low, intermediate and high aluminum diets were  31.1, 32.4 and 30.5 months, respectively.

However, an association between aluminum intake and an accelerated loss of cognitive function was shown by Walton (2009). Beginning in middle age, rats consumed a daily amount of aluminum that would be equivalent to 22, 27 or 92 mg/day for a 120 lb. woman, and 29, 36 or 124 mg/day for a 160 lb. man. Of the 30 rats that survived to at old age, 0/10 on the lowest aluminum dose, 2/10 on the intermediate dose, and 7/10 on the higher dose performed worse on a spatial memory test, when compared with their values in middle age. In addition, rats that performed worse on the test had a significant amount of aluminum deposition in the brain. From these data it can be concluded that increasing dietary aluminum consumption may increase the susceptibility for age-related cognitive decline. In addition, a link between aluminum intake and the brain pathology that is associated with Alzheimer’s disease has been identified (Walton 2006; Walton 2007), but a causative role for aluminum has yet to be proved.

Is the answer then, to eat a diet that eliminates processed foods (and aluminum foil/pots), to reduce risk of cognitive decline? The answer is yes, but there is an overlooked source of aluminum that we all use: deodorant. For example, Gillette Clinical Strength contains 20% (by weight) aluminum. In a 1.7 (48 grams) ounce package, approximately 10 grams of aluminum is present. Assuming use of one deodorant per month, to calculate the daily aluminum exposure we divide the 10 grams by 30 days to obtain ~330 mg aluminum/day. When considering that a diet rich in fruits and vegetables and that eliminates both aluminum containing processed foods and aluminum foil/pots, one would ingest ~10 mg of aluminum per day, absorption of only 25% (~80 mg) of the aluminum present in the Gillette deodorant would place one in the highest quartile of aluminum intake (greater than 100 mg/day), based on Walton’s cognitive function study of 2009. At worst, if all of the aluminum as present in deodorant is absorbed through the skin into the bloodstream, blood levels of aluminum would be more than 3-fold higher than tested in Walton’s rat studies. In other words, even on a pure diet, one could be at risk for high-aluminum related conditions, because of deodorant-based aluminum. Aluminum-free deodorants do exist, and if your goal is to minimize the risk of cognitive decline and potentially, Alzheimer’s disease, buy aluminum-free deodorant!

If you’re interested, please have a look at my book!

References:
Greger JL. Dietary and other sources of aluminium intake.Ciba Found Symp. 1992;169:26-35.

Walton JR. Aluminum in hippocampal neurons from humans with Alzheimer’s disease. Neurotoxicology. 2006 May;27(3):385-94.

Walton JR. A longitudinal study of rats chronically exposed to aluminum at human dietary levels. Neurosci Lett. 2007 Jan 22;412(1):29-33.

Walton JR. Functional impairment in aged rats chronically exposed to human range dietary aluminum equivalents. Neurotoxicology. 2009 Mar;30(2):182-93.