Relevance of access course to become a dietician?

Hi - I'm currently doing an Access to Science course, which includes biology, chemistry and physics, in order to study dietetics at university. However, there are many aspects of this course I'm not enjoying and indeed struggling with, notably in physics, but some aspects of chemistry -- particularly when maths is involved.
So, my question is this -- despite having oodles of life and work experience, a passion for food and nutrition, an interest in health, and a general belief that I'd actually be a great dietician, am I deluding myself? I can understand universities asking for distinctions in biology, and some aspects of chemistry, but when some unis are asking for the full 15 credits at distinction in chemistry, and even some distinctions in physics, I'm finding it a little demoralising.
How much 'maths' do I need to be a dietician? Am I setting myself up to fail?
Thanks