A baby fed on almond milk developed a case of scurvy.

Experts are warning parents that almond milk is not a substitute for a proper, balanced diet. In extreme cases, it can be dangerous.

An 11-month-old baby in Spain fed only almond-milk-based formula developed scurvy because of it.

The disease, which is rare in developed countries, caused the baby to suffer weight loss and bone fractures.

His case was published in the journal Pediatrics, and shows the dangers of plant-based diets for small children.

After being fed a traditional cow-milk-based formula from birth, the boy developed an allergic reaction and at around 2.5 months his diet was changed.

From then on he was fed a diet of almond milk and almond flour.

At around six months the boy’s parents tried to introduce some vegetables and fruit, but did not have any success and continued to feed him the almond milk formula.

He then “showed less interest in interacting and was more unstable when sitting”, the researchers led by Dr. Isidro Vitoria of the Hospital Universitario y Politecnico La Fe in Valencia write in their report.

When he was 11-months-old, the baby’s parents sought medical care for a range of problems, including pain in his legs and irritability.

“The patient was referred for pathologic fractures of the femur, irritability, and failure to thrive,” the journal reports.

He had the typical signs of scurvy, including very low levels of vitamin C in his blood.

Scurvy is mostly associated with sailors, as the condition first developed on ships taking long journeys between the 16th and 18th centuries.

Without any vitamin C rich foods available, the sailors succumbed to the disease.

Vitamin C helps produce collagen and is vital for healthy growth and development.

Experts are concerned that with the rise in plant-based diets in developed nations more children could be vulnerable to this debilitating condition, which is particularly harmful to infants because it effects growth.

“Scurvy is a new and severe complication of improper use of almond drinks in the first year of life. Manufacturers should indicate that these beverages are inappropriate for infants who consume a vitamin C–deficient diet,” the report says.

In the UK, almond milk is now more popular than soy milk, according to supermarket chain Waitrose.