‘Breast is best’ is a saying we are very used to. It is best for the baby in terms of being more resistant to disease, having better growth patterns, less chance of getting diabetes, stomach viruses, respiratory illnesses, ear infections, meningitis and developing allergies.

For mothers, breastfeeding helps reduce the risk of getting breast cancer, ovarian cancer, osteoporosis, cardiovascular disease and obesity.

In poorer contexts breastfeeding can literally be a lifesaver. And in almost all the developing countries we work in, mothers do breastfeed their babies.

So imagine my surprise when I first visited Mexico and found it has one of the lowest rates of breastfeeding in the developing world! Only 18% of babies are ever breastfed. In the UK about 70% of babies are breastfed at birth and about 25% are still breastfeeding at six months. In Sweden the figures are 98% at birth and 68% at six months.

Here, formula milk advertising is seen everywhere. Even in maternity hospitals where free samples of formula milk are also given away. A new law should prevent this happening, but it is slow to take effect.

We did focus groups with women and asked about this issue. The women told us that advertisements had convinced them that formula milk is better than their breastmilk. What a topsy turvey world!

The phone messages we are writing for women in Mexico address these beliefs and try to convince women that their breastmilk really is the perfect food for their baby. And that they can breastfeed exclusively until the baby is six months old and go on feeding until their baby is two years old.

Not all Mexican women are reluctant to breastfeed. One very educated mother told us about taking her still breastfeeding, bright, two-year-old to the beach one day. On this particular beach women were sunbathing topless. Two-year-old son gradually turned round and around looking over the beach. Finally he said; ‘look mummy, a world of milk!’

Maybe there is hope that breastfeeding will become the norm again in Mexico and women will give their baby the best healthful start in life.