Silica: benefits, dosage, side-effects

Silica is a natural compound, found all around us in nature. Silica makes up over a quarter of the planet’s crust and can be found in most rocks, clays and sands. Its forms include emerald, quartz, clay and glass. Silica has multiple uses in industry – for example, in concrete – and in foods, including as an anti-caking agent.¹

In short, it’s everywhere – but how exactly can it help your health? Although it’s now known to be an important trace element, historically silica’s actually been considered more harmful than helpful to our health ­– for example, it’s known that when inhaled in its crystalline form, over time, silica can cause serious lung disease.² But silica comes in many forms.

There’s lots of evidence that its water-soluble form, which is found in certain plants – including the herb horsetail3 – is highly beneficial to health. Traditionally, horsetail has been used to treat wounds, strengthen connective tissue and support the kidneys.⁴

Food sources of silica include:^5,6

• wholegrains
• green beans
• rice
• cucumbers
• tomatoes

Silica is available as tablets and caplets, often extracted from horsetail herb.

The upper safe limit has been reported as 700–1,750 mg a day. As silica is water-soluble, excess is simply passed out by the body in your urine, meaning it’s unlikely to cause side effects if you take too much.¹²

Silica should be avoided by the following people:

Silica is considered safe for healthy people.¹⁵ However, if you decide to get your silica from horsetail herb supplements, be aware that this is not a herb to be used continuously on a long-term basis as it may cause stomach upsets.

The herb’s other actions also mean you need to be careful. For example, horsetail acts as a diuretic so can flush potassium out of the body,¹⁶ which may interfere with certain medications and can lead to problems with your heart rhythm.¹⁷ It also contains an enzyme called thiaminase, which destroys vitamin B1 (thiamine) and can cause symptoms of neurological toxicity in people who are already thiamine-deficient.¹⁸ Some horsetail supplements have the thiaminase removed.

Otherwise, it may be a good idea to take a good quality vitamin B complex supplement or multivitamin if you take horsetail, or to get advice from your doctor. Horsetail herb can cause the following side effects:¹⁹

However, before you take silica, always check with your doctor if you have a long-term condition or are on any medication