Calcium alpha-ketoglutarate (Ca-AKG) – what is it?

Calcium is an essential mineral that plays a role not only in bone formation – for which it is most commonly associated – but also in many other biological processes. Alpha-ketoglutarate, on the other hand, is a natural compound produced in the body during energy metabolism. The combination of alpha-ketoglutarate and calcium forms calcium alpha-ketoglutarate, abbreviated as Ca-AKG. In recent years, this compound has been the subject of increasing research, particularly in relation to metabolism and the processes associated with ageing.

1. What are calcium and calcium alpha-ketoglutarate?
2. Sources of calcium, content and recommended intake
3. Action, forms and dosage of Ca-AKG
4. FAQ – Frequently Asked Questions about Ca-AKG

What are calcium and calcium alpha-ketoglutarate?

Calcium is one of the essential minerals required by the human body. Most of it is found in the bones and teeth, where it is a key component of their structure. Smaller amounts of calcium are present in the blood and other tissues, as this element also plays a role in muscle function, the transmission of nerve impulses, blood clotting and the activity of certain enzymes.

Alpha-ketoglutarate, or AKG, is not a mineral. It is a compound that the body produces itself during the metabolism of nutrients. It is produced, amongst other things, in the citric acid cycle – a series of reactions taking place within cells that enable the body to utilise energy from food. AKG also plays a role in amino acid metabolism and can be converted, amongst other things, into glutamate.

Calcium alpha-ketoglutarate is a combination of these two components. In publications and on labels, it may be referred to as Ca-AKG, CaAKG or calcium alpha-ketoglutarate.

Sources of calcium, content and recommended intake

Milk and dairy products provide the most calcium in a typical diet. A glass of milk may contain around 280–300 mg of calcium, whilst a portion of yoghurt contains around 300–400 mg. Cheeses, particularly hard cheeses, and fish eaten with small bones, such as sardines, can also be good sources. Calcium is also found in plant-based foods.

The situation is different for alpha-ketoglutarate. AKG is not a nutrient whose primary source in the body is food. It is produced primarily within cells during the metabolism of glucose, amino acids and other compounds involved in the citric acid cycle.

The European Food Safety Authority (EFSA) has set the population reference intake for calcium at 1,000 mg per day for people aged 18–24, and 950 mg per day from the age of 25 onwards. These values refer to the total amount of calcium supplied by the diet and any supplements. On food labels, however, a reference intake value of 800 mg per day for an adult is used.

AKG and calcium – the key differences in the ingredients of Ca-AKG

Action, forms and dosage of Ca-AKG

Laboratory experiments and animal studies have analysed the role of AKG in energy metabolism, the regulation of gene activity and processes associated with cellular ageing. However, it cannot currently be confirmed that Ca-AKG slows down ageing, prolongs life or ‘rejuvenates’ the body.

Ca-AKG is most commonly available in capsule or powder form. Some studies have also used sustained-release formulations. However, no official recommended daily dose of Ca-AKG has been established for healthy individuals. The doses used in studies – for example, approximately 1 g per day – should be regarded as part of a specific research protocol rather than as a universal supplementation recommendation.

In the case of preparations containing Ca-AKG, a distinction must also be made between the effects of alpha-ketoglutarate and those of calcium. There are health claims for calcium that have been authorised by the European Union. Among other things, it may be stated that calcium helps maintain healthy bones and teeth, contributes to normal muscle function, normal nerve transmission, normal blood clotting and normal energy metabolism. However, such claims may only be used if the product provides a sufficiently high amount of calcium.

"Ca-AKG combines calcium with alpha-ketoglutarate – a compound that naturally plays a role in cellular metabolism. This is an interesting area of research, particularly in the context of ageing-related processes, but the current evidence does not allow us to regard Ca-AKG as a proven method of slowing down ageing or extending life."

FAQ – Frequently Asked Questions about Ca-AKG

What is Ca-AKG?

Ca-AKG, or calcium alpha-ketoglutarate, is a compound of alpha-ketoglutarate (AKG) and calcium. AKG is a natural compound found in the body that plays a role in, amongst other things, the citric acid cycle and amino acid metabolism.

How does Ca-AKG differ from ordinary calcium?

Calcium is a mineral required, amongst other things, for maintaining healthy bones and proper muscle function. Ca-AKG, however, also contains alpha-ketoglutarate, so the two terms should not be treated as synonymous.

Is Ca-AKG naturally present in food?

AKG is primarily produced within the body during metabolic processes. Ca-AKG, on the other hand, is a form found mainly in dietary supplements, most commonly in capsules or powder form.

Why is Ca-AKG being studied in the context of ageing?

AKG plays a role in important metabolic processes, which is why scientists are investigating its potential impact on processes associated with ageing. Promising results have been obtained, amongst other things, in laboratory and animal studies. However, this does not mean that Ca-AKG has been shown to have anti-ageing effects in humans.

Does Ca-AKG prolong life?

Based on the studies presented, this cannot be confirmed in humans. In a 2020 study, alpha-ketoglutarate supplementation produced interesting results regarding lifespan and healthy lifespan in mice, but such findings cannot be directly extrapolated to humans.

What is the recommended dosage for Ca-AKG?

No official, universal daily dose of Ca-AKG has been established for healthy individuals. Some studies have used approximately 1 g per day, but this dose stems from a specific research protocol rather than a general supplementation recommendation. When taking a supplement, you should first and foremost follow the instructions for use specified for that particular product.

Does Ca-AKG provide calcium?

Yes, as calcium is a component of this compound. However, you should check the label to see how much calcium a specific serving of the product actually provides. The weight of Ca-AKG itself is not equivalent to the same amount of calcium.

How much calcium does an adult need?

According to the figures cited in the article, the EFSA has set the reference intake at 1,000 mg per day for people aged 18–24 and 950 mg from the age of 25. These figures relate to total calcium intake, i.e. primarily from the diet and any supplementation.

Sources:

• Asadi Shahmirzadi, A., Edgar, D., Liao, C. Y., Hsu, Y. M., Lucanic, M., Asadi Shahmirzadi, A., Wiley, C. D., Gan, G., Kim, D. E., Kasler, H. G., Kuehnemann, C., Kaplowitz, B., Bhaumik, D., Riley, R. R., Kennedy, B. K., & Lithgow, G. J. (2020). Alpha-Ketoglutarate, an Endogenous Metabolite, Extends Lifespan and Compresses Morbidity in Aging Mice. Cell metabolism, 32(3), 447–456.e6. https://doi.org/10.1016/j.cmet.2020.08.004
• Gyanwali, B., Lim, Z. X., Soh, J., Lim, C., Guan, S. P., Goh, J., Maier, A. B., & Kennedy, B. K. (2022). Alpha-Ketoglutarate dietary supplementation to improve health in humans. Trends in endocrinology and metabolism: TEM, 33(2), 136–146. https://doi.org/10.1016/j.tem.2021.11.003
• Wu, N., Yang, M., Gaur, U., Xu, H., Yao, Y., & Li, D. (2016). Alpha-Ketoglutarate: Physiological Functions and Applications. Biomolecules & therapeutics, 24(1), 1–8. https://doi.org/10.4062/biomolther.2015.078