Like most baby related topics there is a tonne of information out there - so who do you believe or follow?
WHEN TO START
Places like the MOH or Plunket are great tools for basic information but sadly they can be outdated as it often takes 3-5yrs+ for government related industries to catch up (likely largely due to funding and regulations around changing policies). Don't get me wrong, these are helpful basic places to start if you don't have anywhere else to turn to.
However, there are many studies being carried out/completed around what and when to introduce solids. Some are even kiwi research!!
The biggest take home is don't introduce too early. Whilst the recommendations say between 4 and 6 months, there are very few babies ACTUALLY developmentally ready at 4 months.
Around 4 months they go through a developmental stage of finding their mouth and chewing. Remember babies don't have great neurological feedback from their hands like we do I.e. your sense of touch. For them to decide if an object is hard, soft, fluffy it goes to their lips which are far more sensitive. Around this age as well they start to become a lot more aware of their surroundings - watching and following your movements. Both of these things (objects to mouth, watching you eat) can be misinterpreted for readiness for solids.
Their gut however is what we call porous. That means full of holes - for a simple understanding. Things like food proteins which can't/shouldn't pass through the lining of your gut in adults can pass through in young babies. These proteins can then cause immune responses (eczema/allergies), upset stomachs, and more recent research - the link with introducing grains/cereals too early and IBS/coeliac disease.
The best recommendation is to wait as long as possible until 6 months. This gives the gut a chance to mature, to start to close those holes so that when foods are introduced baby is more likely to handle them. There is no such thing as gentle foods I.e. starting early with kumara or potato, and some cases of eczema or gut issues are from these seemingly "easy to digest" foods given early.
My last take home is don't be afraid to stop if things really aren't working. They have a lifetime to eat and whilst I wouldn't advocate for introducing solids at 12 months, if baby is struggling at 6 months and you need to take a break for a couple of weeks - this is totally ok!
Kekoa's owner Alexis is a midwife and nutritionist and loves to help new parents navigate all that comes with parenting. She regularly presents new topics to help inform you, and always aims for a balanced approach.