In the US there's no significant difference between what a business can deduct and what an individual can deduct. However, you can only deduct what is an expense to produce income.
Businesses are allowed to write off salaries, but individuals can't
write off what they pay their gardener or maid (at least in the US)
If you're a sole proprietor in the business of managing properties - you can definitely deduct payments to gardeners or maids. Business paying for a gardener on a private property not related to producing the income (like CEO's daughter's house) cannot deduct that expense for tax purposes (although it is still recorded in the business accounting books as an expense - with no tax benefit).
Businesses are allowed to deduct utility expenses as overhead, individuals cannot
Same thing exactly. I can deduct utility expenses for my rental property, but not for my primary residence.
Food, shelter, clothing and medical care are fundamental human needs,
but we still pay for them with after-tax money, and pay additional
sales tax. Only interest (and not principal) on a mortgage is
deductible in the US, which is great for people who take out mortgages
(and helps banks get more business, I'm sure), but you're out of luck
if you pay cash for your house, or are renting.
Sales taxes are deductible. You can deduct sales taxes you paid during the year if you itemize your deduction. You can chose - you either deduct the sales taxes or the State income taxes, whatever is more beneficial for you.
BTW in many states food and medicine are exempt from sales tax.
Medical expenses are deductible if they're significant compared to your total income. You can deduct medical expenses in excess of 10% of your AGI. With the ACA kicking in - I don't see how would people even get to that. If your AGI is low you get subsidies for insurance, and the insurance keeps your expenses capped. For self-employed and employed, insurance premiums are pre-tax (i.e.: not even added to your AGI).
Principle for mortgage is not deductible because it is not an expense - it is equity. You own an asset, don't you?
You do get the standard deduction, even if your itemized (real) deductions are less - business don't get that. You also get an exemption amount (for your basic living needs), which businesses don't get. You can argue about the amounts - but it is there.
In some States (like California) renters get tax breaks for renting, depending on the AGI. CA renters credit is phasing out at AGI of about $60K, which is pretty high.