Hi saacsmum
Ds1 has exactly the same food sensitivities, only we didn't realise about the soya one until we'd been feeding him soya formula for a few months. (I wouldn't have given him formula at all had I known what I know now.) Once he came off it, and any other food containing soya, his symptoms disappeared and his weight shot up .
We also use 'Pure' margarine - the sunflower one with the yellow lid. Watch out because the organic version (blue lid) has soya in it.
I have to admit that I like rice milk . Although perhaps I've just got used to it as I haven't drunk any cow's milk for ages. (Ds1 is nearly 3 now.) What variety do you use? We usually have Rice Dream (fortified) but buy Provamel rice milk when Rice Dream isn't available. I've called Provamel to check and their rice milk doesn't contain soya (some of them do, unfortunately).
Other alternatives are oat milks, nut milks, one made from quinoa, and 'Tiger White' which is made from a spanish cactus. All available from health-food shops and starting to be more available in supermarkets too, in the UK at least. I can check the brands if you like as I'm sure some of them should be available where you are. Also, we buy orange juice with added calcium and for a while ds2 didn't have any milk 'substitutes' but just had diluted juice on his cereal.
You're probably getting used to label-scanning, but I'm wary of anything saying 'lecithin' as it is usually soya lecithin (used as an emulsifier). Also loads of baked goods have soya flour in them now, so we never buy anything from in-store bakeries as you can't check the ingredients. We've only found a few varieties of bread that have no soya flour in them. You're in NZ, aren't you? Do the supermarkets do 'free from' lists over there? In the UK many of the supermarkets have jumped onto this bandwagon but so far I've only found a soya-free list at ASDA. It's quite useful to know that, for instance, some of their apple pies don't contain either cow's milk or soya.
I have a great book by Jonathan Brostoff and Linda Gamlyn called 'Food allergies and intolerance'. If you can get hold of one I thoroughly recommend it. As well as giving a thorough background to the science behind reactions to food, it gives you ideas of what to watch out for and what alternatives are available. If you can't get hold of it I can e-mail you the bits about soya and cow's milk if you like.
Another thing I could do is to write down everything we eat for a week or so and send it to you so you have ideas. I was planning to do this for ds's nursery anyway as they seem to have milk and cheese in every meal and can't think of very good alternatives. (I dread to think how they deal with kosher diets.) We do eat meat but some of our meals are vegetarian so it may help you a bit.
Also, if you're a veggie you probably know more than the average person about nutrients but medics and dietitians seem to worry about calorie intake and calcium intake for kids who are non-dairy. I found the UK Vegan Society website (and other vegan sites) useful for non-animal sources of calcium (of which there are loads).
By the time we worked out about ds1's sensitivity to soya he was already weaned off breastmilk but he ate really well so we didn't worry about his calories - and just stopped the formula completely without looking for an alternative. But ds2 is 7 months and only taking very small amounts of solids and we're trying to do the weaning very slowly just in case there are other sensitivities around. So I'm not sure what we will do for a milk substitute when he gets a bit older. But did you realise that the 'hypoallergenic' formulas are still based on cow's milk protein and they can be marketed as 'hypoallergenic' if they cause no reaction in 90% of the kids they are tested on? It's worrying that 10% of the children may still react. Also, the one I was recommended by a dietitian (Nutramigen) also contains soy protein, which she neglected to tell me. So I'm steering clear of any formulas for the moment.
Some people find that goat's milk is okay although at the moment ds1 still reacts even to goat's milk cheddar. But I was brought up on goat's milk and I wonder if it may be better for you to try a goat's milk based formula instead of the 'hypoallergenic' one?
Do you take any supplements yourself, and make sure you get enough calories and fat in your diet? I take a post-natal multivitamin, calcium supplements and DHA supplement because I worry about the effect a restricted diet has on me - and of course there's the higher energy requirement for breastfeeding mums too. I'm not surprised you lost that weight.
I know I've thrown out lots of ideas but few specifics, but I'm typing this late at night and too lazy to go and look things up. Do CAT me if you want more details because it seems that we are in very similar situations and there are all kinds of things that it's taken us a while to realise so I'd like to save you the time if possible.
hth
Sam