Magnesium Glycinate After 60: Does Food Beat the Supplement?

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Magnesium glycinate after 60: does food really work better than the supplement?

A popular claim making the rounds says food beats magnesium glycinate for people over 60. The honest answer is more useful than either side of that framing: it depends entirely on what your diet already looks like, and the research explains exactly why.

What the research actually shows

Start with how magnesium supplements actually get absorbed. A 2001 study in Magnesium Research measured the bioavailability of commercial magnesium preparations in healthy adults and found magnesium oxide, one of the cheapest and most common forms on shelves, was absorbed at only about 4%, while chloride, lactate, and aspartate forms were absorbed significantly better and roughly equivalent to each other (Firoz & Graber, 2001). Glycinate wasn't one of the specific salts tested in this particular trial, but the finding matters here for one reason: "magnesium supplement" isn't one thing, absorption varies enormously by form, and that variability is a big part of why food-vs-supplement comparisons get muddled.

On the food side: a 2025 survey of 309 residents in New Zealand aged-care homes, mean age 85, found more than 80% had usual magnesium intake below the estimated average requirement (MacDonell et al., 2025). Oral nutritional supplements were used by fewer than 10% of residents, but ranked among the top three sources of magnesium for those who did use them. Milk, red meat, and fish were the leading food-based sources. In other words, in this specific older population, most people weren't hitting adequate magnesium from food alone, and the minority using a supplement were getting a meaningful share of their intake from it.

On magnesium glycinate specifically: a 2025 randomised, placebo-controlled trial in Nature and Science of Sleep gave 155 adults reporting poor sleep either 250mg of elemental magnesium as bisglycinate or placebo for four weeks. The supplement group saw a modestly greater improvement in insomnia severity than placebo, a small effect (Cohen's d = 0.2), but the most interesting finding was in the subgroup analysis: people with lower baseline dietary magnesium intake showed notably larger improvements (Schuster et al., 2025). That's the actual mechanism behind the "food vs supplement" debate: glycinate isn't outperforming food in some general sense, it's helping most in exactly the people whose diet isn't providing enough magnesium already.

What this means for you

If your diet reliably includes magnesium-rich foods, leafy greens, nuts, seeds, legumes, whole grains, dairy, and you're not dealing with a condition that affects absorption, a supplement likely won't move the needle much, the trial data itself shows the effect concentrates in people starting from a lower baseline. If you're over 60, eating a limited diet, or in a situation like the aged-care residents above where food-based intake commonly falls short, that's the specific case where a well-absorbed magnesium form is genuinely doing work food alone isn't providing. The claim "food works better" is true for people already eating adequate magnesium; it's not true as a blanket statement for everyone in the age bracket.

The biotype angle

Endomorphs and anyone managing chronic stress or poor sleep, both of which increase magnesium turnover, are the group I'd flag first for checking dietary intake honestly before assuming food alone covers it. Ectomorphs who tend to undereat overall are at similar risk simply from lower total food volume. Mesomorphs in heavy training blocks lose magnesium through sweat at a higher rate, worth factoring in if training volume is high and diet hasn't been adjusted to match.

The honest verdict

Neither "food is always better" nor "everyone over 60 needs a magnesium supplement" holds up against the actual data. The real answer is to check your own dietary intake honestly before deciding, and if it's genuinely inadequate, a well-absorbed form matters more than an oxide-based bargain bottle that the 2001 bioavailability data shows barely gets absorbed. Doctor's Best High Absorption 100% Chelated Magnesium is a reasonable choice if that's your situation, chelated forms clear the absorption bar the poorly-absorbed oxide forms don't. The real limitation: the RCT evidence for glycinate specifically is modest in effect size and short in duration, this is a reasonable, evidence-backed option for people with an actual gap, not a guaranteed fix marketed as one.

For the deep dive on this exact ingredient: → Vitaceuticals MagZorb Magnesium Glycinate 500mg: Science-Backed Review

Want a nutrition plan built around your actual biotype and training load, not a generic supplement list?
→ milenium.com.au/pages/biofit-training

References:
1. Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnes Res. 2001. PMID: 11794633.
2. MacDonell SO, Miller JC, Fleming EA, Haszard JJ. Inadequate Micronutrient Intakes: Exploring the Vitamin and Mineral Intakes and Food Sources of New Zealand Aged-Care Residents. J Hum Nutr Diet. 2025. DOI: 10.1111/jhn.70123. PMID: 40923637.
3. Schuster J, Cycelskij I, Lopresti A, Hahn A. Magnesium Bisglycinate Supplementation in Healthy Adults Reporting Poor Sleep: A Randomized, Placebo-Controlled Trial. Nat Sci Sleep. 2025. DOI: 10.2147/NSS.S524348. PMID: 40918053.