No...
1) Cholesterol: your body makes its own cholesterol from the fat (primarily saturated) you eat anyway. Because too much cholesterol can be a problem, the limit is an upper limit below which you should try to stay. Cholesterol intake upwards of 300mg is associated with increased risk of heart disease since you are adding to the cholesterol your body is making. Even if you ate '0' cholesterol you would be fine becuase your body will make all it needs. All other cholesterol that you eat is extraneous really. So...just stay below 300mg (that would be indicated as 100% but you dont have to reach it, not purposefully anyway!). Unless you actually have a high cholesterol problem in which case you want to stay below 200mg (a maximum of 66% if going according to CC 300mg limit).
2) Sodium certainly has some functions in the body but I'm not exactly sure what they are so yes, you do need it. Too much however has side effects (hypertension, water retention etc) and thus there is the recommended upper limit of 2400mg. Even if you didn't eat any salty foods per se you would probably get all the sodium you need, because the body needs very small amounts, and which are naturally available from fruits and vegetables. It is the added salt that adds up quickly and starts to give the negative effects. But however, if you're like me (hypotensive - very low blood pressure), the doctor recommends that I eat my heart out with salt and I do, because actually I love salt. Now this would not be a problem for hypertension but can lead to water retention. I drink a lot of water though, so I effectively flush out the extra salt and my body never feels it has to hold on to water because I'm not giving it enough. So...you just want to try and stay below the recommended amount. Many even say that the lower the better, but I say - as long as you drink enough water, you're okay up until 2400mg (100% of CC recommendation).
Hope that makes sense.
Lizzy
SALT: Salt is a required nutrient and with too little, the body could dehydrate. The American Heart Association recommends a teaspoon a day. People tend to consume many teaspoons a day which is why so many people try to conciously limit their intake.
Just to add to what sun123 said: certain types of fats (monounsaturated in particular) will help improve your ratio of good to bad cholesetrol but that is not because they contain the 'good' cholesterol...olive oil, nuts and avocados are all cholesterol free and wont affect your cholesterol intake as indicated by the recommendations. Those recommendations refer to the maximum actual cholesterol intake (available from animal fats). In terms of fats though, these (olive oil, nuts and avocados) are definitely the ones you should be eating. They dont contain cholesterol yet they help reduce total cholesterol in the blood, while increasing the ratio of good (high density lipoprotein: HDL) cholesterol to bad (low density lipo...) cholesterol.
It is not entirely accurate to say that saturated fat is the main source of blood cholesterol in the body. According to The China Study: "[S]everal studies have now shown, in both experimental animals and in humans, that consuming animal-based protein increases blood cholesterol levels. Saturated fat and dietary cholesterol also raise blood cholesterol, although these nutrients are not as effective at doing this as is animal protein. In contrast, plant-based foods contain no cholesterol and, in various other ways, help to decrease the amount of cholesterol made by the body."
Animal protein is more effective at raising blood cholesterol levels than either saturated fat or dietary cholesterol intake.
