Some foods protect against heart disease

There may well be some such foods. In industrialised countries like Australia most heart disease is coronary heart disease which refers to narrowing of the coronary arteries by a process called atherosclerosis, commonly referred to as 'hardening of the arteries' (which in fact may be contributed to by other processes). An inadequate blood flow to the heart muscle can lead to angina (chest pain coming from the heart), death of heart muscle (myocardial infarction), abnormal heart rhythms (arrhythmias) or heart failure (cardiac failure).

Mostly we think about heart disease and diet in relation to what it does to the blood cholesterol levels, and how this in turn can contribute to cholesterol deposition in the walls of arteries causing them to narrow. But diet can also influence coronary heart disease by affecting:

blood pressure,
stickiness of blood platelets (increasing the likelihood of artery blockage),
contraction of muscle in the wall of the artery,
fuel supply to the heart,
stability of heart muscle membrane.

One dietary approach to preventing heart disease is to reduce saturated fat (see WHAT WE KNOW ABOUT CHOLESTEROL) in the diet and thereby decrease the amount of cholesterol in blood. Other food factors that may be helpful in lowering blood cholesterol levels include:

Reducing dietary cholesterol (cholesterol is not the same as saturated fat, but is a fat in its own right, found mainly in egg yolks, organ meats such as brain, liver and kidneys, and also in calamari). The effect of decreasing the amount of cholesterol in our diet on the level of cholesterol in blood depends very much on the amount of saturated fats that is also in our diet. People who eat little saturated fat can usually tolerate a little more dietary cholesterol without increasing blood cholesterol.
Increasing dietary polyunsaturated fat of:

(a) the 'omega-6' type (found in seeds and oils or margarines produced from them - see WHAT WE KNOW ABOUT CHOLESTEROL)

(b) the 'omega-3' type (found in fish and fish oils or lean meat).

Increasing the intake of certain pectin-containing plant foods such as citrus and papaya. The effect may be small, but several factors of this kind can add up to a worthwhile effect.
Increasing the intake of legumes.
Increasing the intake of certain other foods such as fungi or mushrooms (suggested by recent work in China); alfalfa sprouts may also be beneficial.

In addition, consuming a low sodium, high potassium diet, and eating more unrefined plant foods like fresh fruit and salads in general, may help to prevent heart disease by acting on factors other than blood cholesterol. One sixteen-year study of London men showed that eating bread, especially wholemeal bread, reduced the risk of heart disease, although its use did not appear to be associated with a lowering of their blood cholesterol.

Inclusion of fish regularly in the diet also seems to reduce risk of coronary heart disease, to an extent that exceeds the expected benefit from just the 'omega-3' fatty acids they contain.

For prevention of coronary heart disease, the total diet must be considered, not just one or two aspects.